Report tracking into wrong Site ID and missing token auth (#13493)

* log tracking failures

* added page

* tweak UI

* use a db column instead of option table to simplify code

* add system summary, notifiy super users by email, fixes, update, ...

* more fixes, needs tests next

* add widget for tracking failures

* ensure to not log any failure when visit is excluded

* some tests and fixes

* added tests

* added missing test

* apply review feedback

* fix tests

* trying to fix test

* fix tests

* fix update names

* fix tests

* Fix another test.

40 files changed, 1062 insertions, 16 deletions

diff --git a/plugins/BulkTracking/tests/Integration/RequestsTest.php b/plugins/BulkTracking/tests/Integration/RequestsTest.php
index 7f6236d82c..e0832770d7 100644
--- a/plugins/BulkTracking/tests/Integration/RequestsTest.php
+++ b/plugins/BulkTracking/tests/Integration/RequestsTest.php
@@ -33,6 +33,8 @@ class RequestsTest extends IntegrationTestCase
     {
         parent::setUp();
 
+        Fixture::createWebsite('2014-01-02 03:04:05');
+
         $this->requests = new Requests();
     }
 
diff --git a/plugins/CoreAdminHome/.gitignore b/plugins/CoreAdminHome/.gitignore
new file mode 100644
index 0000000000..c8c9480010
--- /dev/null
+++ b/plugins/CoreAdminHome/.gitignore
@@ -0,0 +1 @@
+tests/System/processed/*xml
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/API.php b/plugins/CoreAdminHome/API.php
index 6fc3313696..19eef3d946 100644
--- a/plugins/CoreAdminHome/API.php
+++ b/plugins/CoreAdminHome/API.php
@@ -11,6 +11,7 @@ namespace Piwik\Plugins\CoreAdminHome;
 use Exception;
 use Monolog\Handler\StreamHandler;
 use Monolog\Logger;
+use Piwik\Access;
 use Piwik\ArchiveProcessor\Rules;
 use Piwik\Config;
 use Piwik\Container\StaticContainer;
@@ -22,6 +23,7 @@ use Piwik\Piwik;
 use Piwik\Segment;
 use Piwik\Scheduler\Scheduler;
 use Piwik\Site;
+use Piwik\Tracker\Failures;
 use Piwik\Url;
 
 /**
@@ -39,10 +41,16 @@ class API extends \Piwik\Plugin\API
      */
     private $invalidator;
 
-    public function __construct(Scheduler $scheduler, ArchiveInvalidator $invalidator)
+    /**
+     * @var Failures
+     */
+    private $trackingFailures;
+
+    public function __construct(Scheduler $scheduler, ArchiveInvalidator $invalidator, Failures $trackingFailures)
     {
         $this->scheduler = $scheduler;
         $this->invalidator = $invalidator;
+        $this->trackingFailures = $trackingFailures;
     }
 
     /**
@@ -180,6 +188,55 @@ class API extends \Piwik\Plugin\API
     }
 
     /**
+     * Deletes all tracking failures this user has at least admin access to.
+     * A super user will also delete tracking failures for sites that don't exist.
+     */
+    public function deleteAllTrackingFailures()
+    {
+        if (Piwik::hasUserSuperUserAccess()) {
+            $this->trackingFailures->deleteAllTrackingFailures();
+        } else {
+            Piwik::checkUserHasSomeAdminAccess();
+            $idSites = Access::getInstance()->getSitesIdWithAdminAccess();
+            Piwik::checkUserHasAdminAccess($idSites);
+            $this->trackingFailures->deleteTrackingFailures($idSites);
+        }
+    }
+
+    /**
+     * Deletes a specific tracking failure
+     * @param int $idSite
+     * @param int $idFailure
+     */
+    public function deleteTrackingFailure($idSite, $idFailure)
+    {
+        $idSite = (int) $idSite;
+        Piwik::checkUserHasAdminAccess($idSite);
+
+        $this->trackingFailures->deleteTrackingFailure($idSite, $idFailure);
+    }
+
+    /**
+     * Get all tracking failures. A user retrieves only tracking failures for sites with at least admin access.
+     * A super user will also retrieve failed requests for sites that don't exist.
+     * @return array
+     */
+    public function getTrackingFailures()
+    {
+        if (Piwik::hasUserSuperUserAccess()) {
+            $failures = $this->trackingFailures->getAllFailures();
+        } else {
+            Piwik::checkUserHasSomeAdminAccess();
+            $idSites = Access::getInstance()->getSitesIdWithAdminAccess();
+            Piwik::checkUserHasAdminAccess($idSites);
+
+            $failures = $this->trackingFailures->getFailuresForSites($idSites);
+        }
+
+        return $failures;
+    }
+
+    /**
      * Ensure the specified dates are valid.
      * Store invalid date so we can log them
      * @param array $dates
diff --git a/plugins/CoreAdminHome/Controller.php b/plugins/CoreAdminHome/Controller.php
index bee4b57cac..32441e0d39 100644
--- a/plugins/CoreAdminHome/Controller.php
+++ b/plugins/CoreAdminHome/Controller.php
@@ -60,6 +60,7 @@ class Controller extends ControllerAdmin
         $hasPremiumFeatures = $widgetsList->isDefined('Marketplace', 'getPremiumFeatures');
         $hasNewPlugins = $widgetsList->isDefined('Marketplace', 'getNewPlugins');
         $hasDiagnostics = $widgetsList->isDefined('Installation', 'getSystemCheck');
+        $hasTrackingFailures = $widgetsList->isDefined('CoreAdminHome', 'getTrackingFailures');
 
         return $this->renderTemplate('home', array(
             'isInternetEnabled' => $isInternetEnabled,
@@ -70,6 +71,7 @@ class Controller extends ControllerAdmin
             'hasDonateForm' => $hasDonateForm,
             'hasPiwikBlog' => $hasPiwikBlog,
             'hasDiagnostics' => $hasDiagnostics,
+            'hasTrackingFailures' => $hasTrackingFailures,
         ));
     }
 
@@ -79,6 +81,13 @@ class Controller extends ControllerAdmin
         return;
     }
 
+    public function trackingFailures()
+    {
+        Piwik::checkUserHasSomeAdminAccess();
+
+        return $this->renderTemplate('trackingFailures');
+    }
+
     public function generalSettings()
     {
         Piwik::checkUserHasSuperUserAccess();
diff --git a/plugins/CoreAdminHome/CoreAdminHome.php b/plugins/CoreAdminHome/CoreAdminHome.php
index a87c6da948..3e0d0e4912 100644
--- a/plugins/CoreAdminHome/CoreAdminHome.php
+++ b/plugins/CoreAdminHome/CoreAdminHome.php
@@ -8,10 +8,10 @@
  */
 namespace Piwik\Plugins\CoreAdminHome;
 
-use Piwik\Db;
+use Piwik\API\Request;
 use Piwik\Piwik;
 use Piwik\ProxyHttp;
-use Piwik\Settings\Plugin\UserSetting;
+use Piwik\Plugins\CoreHome\SystemSummary;
 use Piwik\Settings\Storage\Backend\PluginSettingsTable;
 
 /**
@@ -20,7 +20,7 @@ use Piwik\Settings\Storage\Backend\PluginSettingsTable;
 class CoreAdminHome extends \Piwik\Plugin
 {
     /**
-     * @see Piwik\Plugin::registerEvents
+     * @see \Piwik\Plugin::registerEvents
      */
     public function registerEvents()
     {
@@ -30,10 +30,24 @@ class CoreAdminHome extends \Piwik\Plugin
             'UsersManager.deleteUser'         => 'cleanupUser',
             'API.DocumentationGenerator.@hideExceptForSuperUser' => 'displayOnlyForSuperUser',
             'Template.jsGlobalVariables' => 'addJsGlobalVariables',
-            'Translate.getClientSideTranslationKeys' => 'getClientSideTranslationKeys'
+            'Translate.getClientSideTranslationKeys' => 'getClientSideTranslationKeys',
+            'System.addSystemSummaryItems' => 'addSystemSummaryItems',
         );
     }
 
+    public function addSystemSummaryItems(&$systemSummary)
+    {
+        if (Piwik::isUserHasSomeAdminAccess()) {
+            $failures = Request::processRequest('CoreAdminHome.getTrackingFailures', [], []);
+            $numFailures = count($failures);
+            $icon = 'icon-error';
+            if ($numFailures === 0) {
+                $icon = 'icon-ok';
+            }
+            $systemSummary[] = new SystemSummary\Item($key = 'trackingfailures', Piwik::translate('CoreAdminHome_NTrackingFailures', $numFailures), $value = null, array('module' => 'CoreAdminHome', 'action' => 'trackingFailures'), $icon, $order = 9);
+        }
+    }
+
     public function cleanupUser($userLogin)
     {
         PluginSettingsTable::removeAllUserSettingsForUser($userLogin);
@@ -45,6 +59,7 @@ class CoreAdminHome extends \Piwik\Plugin
         $stylesheets[] = "plugins/Morpheus/stylesheets/base.less";
         $stylesheets[] = "plugins/Morpheus/stylesheets/main.less";
         $stylesheets[] = "plugins/CoreAdminHome/stylesheets/generalSettings.less";
+        $stylesheets[] = "plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.less";
     }
 
     public function getJsFiles(&$jsFiles)
@@ -82,5 +97,23 @@ class CoreAdminHome extends \Piwik\Plugin
         $translationKeys[] = 'CoreAdminHome_ProtocolNotDetectedCorrectlySolution';
         $translationKeys[] = 'CoreAdminHome_SettingsSaveSuccess';
         $translationKeys[] = 'UserCountryMap_None';
+        $translationKeys[] = 'Actions_ColumnPageURL';
+        $translationKeys[] = 'General_Date';
+        $translationKeys[] = 'General_Measurable';
+        $translationKeys[] = 'General_Action';
+        $translationKeys[] = 'General_Delete';
+        $translationKeys[] = 'General_Id';
+        $translationKeys[] = 'CoreHome_ClickToSeeFullInformation';
+        $translationKeys[] = 'CoreAdminHome_LearnMore';
+        $translationKeys[] = 'CoreAdminHome_ConfirmDeleteAllTrackingFailures';
+        $translationKeys[] = 'CoreAdminHome_ConfirmDeleteThisTrackingFailure';
+        $translationKeys[] = 'CoreAdminHome_DeleteAllFailures';
+        $translationKeys[] = 'CoreAdminHome_NTrackingFailures';
+        $translationKeys[] = 'CoreAdminHome_Problem';
+        $translationKeys[] = 'CoreAdminHome_Solution';
+        $translationKeys[] = 'CoreAdminHome_TrackingFailures';
+        $translationKeys[] = 'CoreAdminHome_TrackingFailuresIntroduction';
+        $translationKeys[] = 'CoreAdminHome_TrackingURL';
+        $translationKeys[] = 'CoreAdminHome_NoKnownFailures';
     }
 }
diff --git a/plugins/CoreAdminHome/Emails/TrackingFailuresEmail.php b/plugins/CoreAdminHome/Emails/TrackingFailuresEmail.php
new file mode 100644
index 0000000000..92d3ee2c16
--- /dev/null
+++ b/plugins/CoreAdminHome/Emails/TrackingFailuresEmail.php
@@ -0,0 +1,106 @@
+<?php
+/**
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ *
+ */
+
+namespace Piwik\Plugins\CoreAdminHome\Emails;
+
+use Piwik\Access;
+use Piwik\Mail;
+use Piwik\Piwik;
+use Piwik\SettingsPiwik;
+use Piwik\Url;
+use Piwik\View;
+
+class TrackingFailuresEmail extends Mail
+{
+    /**
+     * @var string
+     */
+    private $login;
+
+    /**
+     * @var string
+     */
+    private $emailAddress;
+
+    /**
+     * @var int
+     */
+    private $numFailures;
+
+    public function __construct($login, $emailAddress, $numFailures)
+    {
+        parent::__construct();
+
+        $this->login = $login;
+        $this->emailAddress = $emailAddress;
+        $this->numFailures = (int)$numFailures;
+
+        $this->setUpEmail();
+    }
+
+    /**
+     * @return string
+     */
+    public function getLogin()
+    {
+        return $this->login;
+    }
+
+    /**
+     * @return string
+     */
+    public function getEmailAddress()
+    {
+        return $this->emailAddress;
+    }
+
+    /**
+     * @return int
+     */
+    public function getNumFailures()
+    {
+        return $this->numFailures;
+    }
+
+    private function setUpEmail()
+    {
+        $this->setDefaultFromPiwik();
+        $this->addTo($this->emailAddress);
+        $this->setSubject($this->getDefaultSubject());
+        $this->setReplyTo($this->getFrom());
+        $this->setWrappedHtmlBody($this->getDefaultBodyView());
+    }
+
+    private function getDefaultSubject()
+    {
+        return Piwik::translate('CoreAdminHome_TrackingFailuresEmailSubject');
+    }
+
+    private function getDefaultBodyView()
+    {
+        $view = new View('@CoreAdminHome/_trackingFailuresEmail.twig');
+        $view->login = $this->login;
+        $view->emailAddress = $this->emailAddress;
+        $view->numFailures = $this->numFailures;
+
+        $sitesId = Access::getInstance()->getSitesIdWithAtLeastViewAccess();
+        $idSite = false;
+        if (!empty($sitesId)) {
+            $idSite = array_shift($sitesId);
+        }
+        $view->trackingFailuresUrl = SettingsPiwik::getPiwikUrl() . 'index.php?' . Url::getQueryStringFromParameters([
+            'module' => 'CoreAdminHome',
+            'action' => 'trackingFailures',
+            'period' => 'day',
+            'date' => 'yesterday',
+            'idSite' => $idSite
+        ]);
+        return $view;
+    }
+}
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/Menu.php b/plugins/CoreAdminHome/Menu.php
index 49a5579636..8ec288ec6c 100644
--- a/plugins/CoreAdminHome/Menu.php
+++ b/plugins/CoreAdminHome/Menu.php
@@ -36,6 +36,12 @@ class Menu extends \Piwik\Plugin\Menu
                 $this->urlForAction('trackingCodeGenerator'),
                 $order = 12);
         }
+
+        if (Piwik::isUserHasSomeAdminAccess()) {
+            $menu->addDiagnosticItem('CoreAdminHome_TrackingFailures',
+                $this->urlForAction('trackingFailures'),
+                $order = 2);
+        }
     }
 
     public function configureTopMenu(MenuTop $menu)
diff --git a/plugins/CoreAdminHome/Tasks.php b/plugins/CoreAdminHome/Tasks.php
index 80560dde48..e6c7d1b242 100644
--- a/plugins/CoreAdminHome/Tasks.php
+++ b/plugins/CoreAdminHome/Tasks.php
@@ -18,13 +18,14 @@ use Piwik\Date;
 use Piwik\Db;
 use Piwik\Http;
 use Piwik\Option;
+use Piwik\Piwik;
 use Piwik\Plugins\CoreAdminHome\Emails\JsTrackingCodeMissingEmail;
+use Piwik\Plugins\CoreAdminHome\Emails\TrackingFailuresEmail;
 use Piwik\Plugins\CoreAdminHome\Tasks\ArchivesToPurgeDistributedList;
 use Piwik\Plugins\SitesManager\SitesManager;
-use Piwik\Scheduler\Schedule\Daily;
-use Piwik\Scheduler\Schedule\Monthly;
 use Piwik\Scheduler\Schedule\SpecificTime;
 use Piwik\Settings\Storage\Backend\MeasurableSettingsTable;
+use Piwik\Tracker\Failures;
 use Piwik\Site;
 use Piwik\Tracker\Visit\ReferrerSpamFilter;
 use Psr\Log\LoggerInterface;
@@ -43,10 +44,16 @@ class Tasks extends \Piwik\Plugin\Tasks
      */
     private $logger;
 
-    public function __construct(ArchivePurger $archivePurger, LoggerInterface $logger)
+    /**
+     * @var Failures
+     */
+    private $trackingFailures;
+
+    public function __construct(ArchivePurger $archivePurger, LoggerInterface $logger, Failures $failures)
     {
         $this->archivePurger = $archivePurger;
         $this->logger = $logger;
+        $this->trackingFailures = $failures;
     }
 
     public function schedule()
@@ -60,6 +67,9 @@ class Tasks extends \Piwik\Plugin\Tasks
         // lowest priority since tables should be optimized after they are modified
         $this->daily('optimizeArchiveTable', null, self::LOWEST_PRIORITY);
 
+        $this->daily('cleanupTrackingFailures', null, self::LOWEST_PRIORITY);
+        $this->weekly('notifyTrackingFailures', null, self::LOWEST_PRIORITY);
+
         if(SettingsPiwik::isInternetEnabled() === true){
             $this->weekly('updateSpammerBlacklist');
         }
@@ -140,6 +150,36 @@ class Tasks extends \Piwik\Plugin\Tasks
     }
 
     /**
+     * To test execute the following command:
+     * `./console core:run-scheduled-tasks "Piwik\Plugins\CoreAdminHome\Tasks.cleanupTrackingFailures"`
+     *
+     * @throws \Exception
+     */
+    public function cleanupTrackingFailures()
+    {
+        // we remove possibly outdated/fixed tracking failures that have not occurred again recently
+        $this->trackingFailures->removeFailuresOlderThanDays(Failures::CLEANUP_OLD_FAILURES_DAYS);
+    }
+
+    /**
+     * To test execute the following command:
+     * `./console core:run-scheduled-tasks "Piwik\Plugins\CoreAdminHome\Tasks.notifyTrackingFailures"`
+     *
+     * @throws \Exception
+     */
+    public function notifyTrackingFailures()
+    {
+        $failures = $this->trackingFailures->getAllFailures();
+        if (!empty($failures)) {
+            $superUsers = Piwik::getAllSuperUserAccessEmailAddresses();
+            foreach ($superUsers as $login => $email) {
+                $email = new TrackingFailuresEmail($login, $email, count($failures));
+                $email->send();
+            }
+        }
+    }
+
+    /**
      * @return bool `true` if the purge was executed, `false` if it was skipped.
      * @throws \Exception
      */
diff --git a/plugins/CoreAdminHome/Widgets/GetTrackingFailures.php b/plugins/CoreAdminHome/Widgets/GetTrackingFailures.php
new file mode 100644
index 0000000000..c251c3c92f
--- /dev/null
+++ b/plugins/CoreAdminHome/Widgets/GetTrackingFailures.php
@@ -0,0 +1,39 @@
+<?php
+/**
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ *
+ */
+namespace Piwik\Plugins\CoreAdminHome\Widgets;
+
+use Piwik\API\Request;
+use Piwik\Piwik;
+use Piwik\Widget\Widget;
+use Piwik\Widget\WidgetConfig;
+
+class GetTrackingFailures extends Widget
+{
+    public static function configure(WidgetConfig $config)
+    {
+        $config->setCategoryId('About Matomo');
+        $config->setName('CoreAdminHome_TrackingFailures');
+        $config->setOrder(5);
+
+        if (!Piwik::isUserHasSomeAdminAccess()) {
+            $config->disable();
+        }
+    }
+
+    public function render()
+    {
+        Piwik::checkUserHasSomeAdminAccess();
+        $failures = Request::processRequest('CoreAdminHome.getTrackingFailures');
+        $numFailures = count($failures);
+
+        return $this->renderTemplate('getTrackingFailures', array(
+            'numFailures' => $numFailures
+        ));
+    }
+}
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.controller.js b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.controller.js
new file mode 100644
index 0000000000..e007fae6c3
--- /dev/null
+++ b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.controller.js
@@ -0,0 +1,59 @@
+/*!
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+(function () {
+    angular.module('piwikApp').controller('TrackingFailuresController', TrackingFailuresController);
+
+    TrackingFailuresController.$inject = ['piwikApi', 'piwik'];
+
+    function TrackingFailuresController(piwikApi, piwik){
+        var self = this;
+        this.failures = [];
+        this.sortColumn = 'idsite';
+        this.sortReverse = false;
+        this.isLoading = false;
+
+        this.changeSortOrder = function (columnToSort) {
+            if (this.sortColumn === columnToSort) {
+                this.sortReverse = !this.sortReverse;
+            } else {
+                this.sortColumn = columnToSort;
+            }
+        };
+
+        this.fetchAll = function () {
+            this.failures = [];
+            this.isLoading = true;
+            piwikApi.fetch({method: 'CoreAdminHome.getTrackingFailures', filter_limit: '-1'}).then(function (failures) {
+                self.failures = failures;
+                self.isLoading = false;
+            }, function () {
+                self.isLoading = false;
+            });
+        };
+
+        this.deleteAll = function () {
+            piwik.helper.modalConfirm('#confirmDeleteAllTrackingFailures', {yes: function () {
+                self.failures = [];
+                piwikApi.fetch({method: 'CoreAdminHome.deleteAllTrackingFailures'}).then(function () {
+                    self.fetchAll();
+                });
+            }});
+        };
+
+        this.deleteFailure = function (idSite, idFailure) {
+            piwik.helper.modalConfirm('#confirmDeleteThisTrackingFailure', {yes: function () {
+                self.failures = [];
+                piwikApi.fetch({method: 'CoreAdminHome.deleteTrackingFailure', idSite: idSite, idFailure: idFailure}).then(function () {
+                    self.fetchAll();
+                });
+            }});
+        };
+
+        this.fetchAll();
+    }
+
+})();
diff --git a/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.html b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.html
new file mode 100644
index 0000000000..07e4baa895
--- /dev/null
+++ b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.html
@@ -0,0 +1,59 @@
+<div piwik-content-block
+     content-title="{{ 'CoreAdminHome_TrackingFailures'|translate }}"
+     class="matomoTrackingFailures">
+    <p>
+        {{ 'CoreAdminHome_TrackingFailuresIntroduction'|translate:2 }}
+        <br /><br />
+        <input class="btn deleteAllFailures"
+               ng-show="!trackingFailures.isLoading && trackingFailures.failures.length > 0"
+               type="button" ng-click="trackingFailures.deleteAll();"
+               value="{{'CoreAdminHome_DeleteAllFailures'|translate}}">
+    </p>
+
+    <div piwik-activity-indicator loading="trackingFailures.isLoading"></div>
+
+    <table piwik-content-table>
+        <thead>
+        <tr>
+            <th ng-click="trackingFailures.changeSortOrder('idsite')">{{ 'General_Measurable'|translate }}</th>
+            <th ng-click="trackingFailures.changeSortOrder('problem')">{{ 'CoreAdminHome_Problem'|translate }}</th>
+            <th ng-click="trackingFailures.changeSortOrder('solution')">{{ 'CoreAdminHome_Solution'|translate }}</th>
+            <th ng-click="trackingFailures.changeSortOrder('date_first_occurred')">{{ 'General_Date'|translate }}</th>
+            <th ng-click="trackingFailures.changeSortOrder('url')">{{ 'Actions_ColumnPageURL'|translate }}</th>
+            <th ng-click="trackingFailures.changeSortOrder('request_url')">{{ 'CoreAdminHome_TrackingURL'|translate }}</th>
+            <th class="action">{{ 'General_Action'|translate }}</th>
+        </tr>
+        </thead>
+        <tbody>
+        <tr><td colspan="7" ng-show="!trackingFailures.isLoading && trackingFailures.failures.length == 0">{{'CoreAdminHome_NoKnownFailures'|translate}} <span class="icon-ok"></span></td></tr>
+            <tr ng-repeat="failure in trackingFailures.failures | orderBy:trackingFailures.sortColumn:trackingFailures.sortReverse">
+                <td>{{ failure.site_name }} ({{'General_Id'|translate}} {{ failure.idsite }})</td>
+                <td>{{ failure.problem }}</td>
+                <td>{{ failure.solution }} <a ng-show="failure.solution_url" rel="noopener noreferrer" ng-href="{{ failure.solution_url }}">{{'CoreAdminHome_LearnMore'|translate }}</a></td>
+                <td class="datetime">{{ failure.pretty_date_first_occurred }}</td>
+                <td>{{ failure.url }}</td>
+                <td><span ng-show="!failure.showFullRequestUrl" title="{{'CoreHome_ClickToSeeFullInformation'|translate}}"
+                          ng-click="failure.showFullRequestUrl = true">{{ failure.request_url|limitTo:100 }}...</span>
+                    <span ng-show="failure.showFullRequestUrl">{{ failure.request_url }}</span></td>
+                <td><span class="table-action icon-delete"
+                          title="{{'General_Delete'|translate}}"
+                          ng-click="trackingFailures.deleteFailure(failure.idsite, failure.idfailure)"></span></td>
+            </tr>
+        </tbody>
+    </table>
+
+    <div class="ui-confirm" id="confirmDeleteAllTrackingFailures">
+        <h2>{{ 'CoreAdminHome_ConfirmDeleteAllTrackingFailures'|translate }}</h2>
+
+        <input type="button" value="{{ 'General_Yes'|translate }}" role="yes"/>
+        <input type="button" value="{{ 'General_No'|translate }}" role="no" />
+    </div>
+
+    <div class="ui-confirm" id="confirmDeleteThisTrackingFailure">
+        <h2>{{ 'CoreAdminHome_ConfirmDeleteThisTrackingFailure'|translate }}</h2>
+
+        <input type="button" value="{{ 'General_Yes'|translate }}" role="yes"/>
+        <input type="button" value="{{ 'General_No'|translate }}" role="no" />
+    </div>
+
+</div>
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.js b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.js
new file mode 100644
index 0000000000..910e5278d7
--- /dev/null
+++ b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.js
@@ -0,0 +1,25 @@
+/*!
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+/**
+ * Usage:
+ * <div matomo-tracking-failures>
+ */
+(function () {
+    angular.module('piwikApp').directive('matomoTrackingFailures', matomoTrackingFailures);
+
+    matomoTrackingFailures.$inject = ['piwik'];
+
+    function matomoTrackingFailures(piwik){
+        return {
+            restrict: 'A',
+            templateUrl: 'plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.html?cb=' + piwik.cacheBuster,
+            controller: 'TrackingFailuresController',
+            controllerAs: 'trackingFailures'
+        };
+    }
+})();
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.less b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.less
new file mode 100644
index 0000000000..505b106431
--- /dev/null
+++ b/plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.less
@@ -0,0 +1,9 @@
+.matomoTrackingFailures {
+    .icon-delete,
+    th:not(.action) {
+        cursor: pointer;
+    }
+    th.action {
+        width: 60px;
+    }
+}
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/config/test.php b/plugins/CoreAdminHome/config/test.php
new file mode 100644
index 0000000000..13a2080dae
--- /dev/null
+++ b/plugins/CoreAdminHome/config/test.php
@@ -0,0 +1,30 @@
+<?php
+use \Piwik\Tracker\Request;
+use \Piwik\Tracker\Failures;
+
+return array(
+
+    'Piwik\Tracker\Failures' => DI\decorate(function ($previous) {
+        /** @var Failures $previous */
+
+        $generate = \Piwik\Container\StaticContainer::get('test.vars.generateTrackingFailures');
+        if ($generate) {
+            $previous->setNow(\Piwik\Date::factory('2018-07-07 01:02:03'));
+            $previous->logFailure(Failures::FAILURE_ID_INVALID_SITE, new Request(array(
+                'idsite' => 998, 'rec' => '1'
+            )));
+            $previous->logFailure(Failures::FAILURE_ID_NOT_AUTHENTICATED, new Request(array(
+                'idsite' => 1,
+                'url' => 'https://www.example.com/foo/bar?x=1',
+                'action_name' => 'foobar',
+                'rec' => '1'
+            )));
+            $previous->logFailure(Failures::FAILURE_ID_INVALID_SITE, new Request(array(
+                'idsite' => 999, 'rec' => '1'
+            )));
+        }
+
+        return $previous;
+    }),
+
+);
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/lang/en.json b/plugins/CoreAdminHome/lang/en.json
index 25ae8e094f..ac3328f395 100644
--- a/plugins/CoreAdminHome/lang/en.json
+++ b/plugins/CoreAdminHome/lang/en.json
@@ -82,6 +82,7 @@
         "PluginSettingsValueNotAllowed": "The value for field \"%1$s\" in plugin \"%2$s\" is not allowed",
         "PluginSettingsSaveFailed": "Failed to save plugin settings",
         "PluginSettingsSaveSuccess": "Plugin settings updated.",
+        "TrackingFailures": "Tracking failures",
         "SettingsSaveSuccess": "Settings updated.",
         "SendPluginUpdateCommunication": "Send an email when a plugin update is available",
         "SendPluginUpdateCommunicationHelp": "An email will be sent to Super Users when there is a new version available for a plugin.",
@@ -108,6 +109,24 @@
         "MissingTrackingCodeEmailSubject": "No traffic for %s recorded in Matomo Analytics, get started now",
         "JsTrackingCodeMissingEmail1": "A few days ago you added the website '%s' to your Matomo Analytics. We just checked and your Matomo doesn't seem to have any recorded traffic for this website.",
         "JsTrackingCodeMissingEmail2": "To begin tracking data and getting insights into your users, you'll need to setup tracking in your website or mobile app. For websites simply embed the tracking code right before the %s tag.",
-        "JsTrackingCodeMissingEmail3": "To find and customize your tracking code, %1$sclick here%2$s (or have a look at the %3$sJavaScript Tracking Client guide%4$s)."
+        "JsTrackingCodeMissingEmail3": "To find and customize your tracking code, %1$sclick here%2$s (or have a look at the %3$sJavaScript Tracking Client guide%4$s).",
+        "TrackingFailuresIntroduction": "This page lists tracking failures that happened during the last %s days. Please note that only the most common kind of tracking failures are recorded and not all of them.",
+        "NoKnownFailures": "There are no known tracking failures.",
+        "Problem": "Problem",
+        "Solution": "Solution",
+        "TrackingURL": "Tracking URL",
+        "LearnMore": "Learn more",
+        "DeleteAllFailures": "Delete all failures",
+        "NTrackingFailures": "%s tracking failures",
+        "ViewAllTrackingFailures": "View all tracking failures",
+        "TrackingFailureInvalidSiteProblem": "The site does not exist.",
+        "TrackingFailureInvalidSiteSolution": "Update the configured idSite in the tracker.",
+        "TrackingFailureAuthenticationProblem": "Request was not authenticated but authentication was required.",
+        "TrackingFailureAuthenticationSolution": "Set or correct a \"token_auth\" in your tracking request.",
+        "ConfirmDeleteAllTrackingFailures": "Are you sure you want to delete all tracking failures?",
+        "ConfirmDeleteThisTrackingFailure": "Are you sure you want to delete this tracking failure?",
+        "TrackingFailuresEmailSubject": "Tracking failures in your Matomo Analytics",
+        "TrackingFailuresEmail1": "This is just to let you know that %s different kinds of tracking failures have occurred in the last days.",
+        "TrackingFailuresEmail2": "To view all the failed tracking requests %1$sclick here%2$s."
     }
 }
diff --git a/plugins/CoreAdminHome/templates/_trackingFailuresEmail.twig b/plugins/CoreAdminHome/templates/_trackingFailuresEmail.twig
new file mode 100644
index 0000000000..8be51c0e0d
--- /dev/null
+++ b/plugins/CoreAdminHome/templates/_trackingFailuresEmail.twig
@@ -0,0 +1,3 @@
+<p>{{ 'General_HelloUser'|translate(login) }}</p>
+<p>{{ 'CoreAdminHome_TrackingFailuresEmail1'|translate('<strong>'~numFailures~'</strong>')|raw }}</p>
+<p>{{ 'CoreAdminHome_TrackingFailuresEmail2'|translate('<a href="'~trackingFailuresUrl~'">', '</a>')|raw }}</p>
diff --git a/plugins/CoreAdminHome/templates/getTrackingFailures.twig b/plugins/CoreAdminHome/templates/getTrackingFailures.twig
new file mode 100644
index 0000000000..3096e65c2f
--- /dev/null
+++ b/plugins/CoreAdminHome/templates/getTrackingFailures.twig
@@ -0,0 +1,13 @@
+<div class="widgetBody system-check">
+    {% if numFailures == 0 %}
+        <p class="system-success"><span class="icon-ok"></span> {{ 'CoreAdminHome_NoKnownFailures'|translate }}</p>
+    {% else %}
+        <p class="system-errors">
+            <span style="font-size: 16px;"><span class="icon-error"></span> {{ 'CoreAdminHome_NTrackingFailures'|translate(numFailures) }}</span>
+        </p>
+        <p>
+            <a href="{{ linkTo({'module': 'CoreAdminHome', 'action': 'trackingFailures'}) }}"
+            >{{ 'CoreAdminHome_ViewAllTrackingFailures'|translate }}</a>
+        </p>
+    {% endif %}
+</div>
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/templates/home.twig b/plugins/CoreAdminHome/templates/home.twig
index 58c3288c19..0c52fdf9c1 100644
--- a/plugins/CoreAdminHome/templates/home.twig
+++ b/plugins/CoreAdminHome/templates/home.twig
@@ -21,9 +21,14 @@
             <div class="col s12 {% if isFeedbackEnabled %}m4{% else %}m6{% endif %}">
                 <div piwik-widget-loader='{"module":"CoreHome","action":"getSystemSummary"}'></div>
             </div>
-            {% if hasDiagnostics %}
+            {% if hasDiagnostics or hasTrackingFailures %}
                 <div class="col s12 {% if isFeedbackEnabled %}m4{% else %}m6{% endif %}">
+                    {% if hasDiagnostics %}
                     <div piwik-widget-loader='{"module":"Installation","action":"getSystemCheck"}'></div>
+                    {% endif %}
+                    {% if hasTrackingFailures %}
+                    <div piwik-widget-loader='{"module":"CoreAdminHome","action":"getTrackingFailures"}'></div>
+                    {% endif %}
                 </div>
             {% endif %}
             {% if isFeedbackEnabled %}
diff --git a/plugins/CoreAdminHome/templates/trackingFailures.twig b/plugins/CoreAdminHome/templates/trackingFailures.twig
new file mode 100644
index 0000000000..36c2347e2e
--- /dev/null
+++ b/plugins/CoreAdminHome/templates/trackingFailures.twig
@@ -0,0 +1,8 @@
+{% extends 'admin.twig' %}
+
+{% set title %}{{ 'CoreAdminHome_TrackingFailures'|translate }}{% endset %}
+
+{% block content %}
+    <div matomo-tracking-failures>
+    </div>
+{% endblock %}
diff --git a/plugins/CoreAdminHome/tests/Fixture/TrackingFailures.php b/plugins/CoreAdminHome/tests/Fixture/TrackingFailures.php
new file mode 100644
index 0000000000..f8ab0cb808
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/Fixture/TrackingFailures.php
@@ -0,0 +1,46 @@
+<?php
+/**
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+namespace Piwik\Plugins\CoreAdminHome\tests\Fixture;
+
+use Piwik\Date;
+use Piwik\Tests\Framework\Fixture;
+
+class TrackingFailures extends Fixture
+{
+    public $idSite = 1;
+    public $dateTime = '2013-01-02 03:04:05';
+
+    public function setUp()
+    {
+        parent::setUp();
+
+        Fixture::createSuperUser();
+        if (!self::siteCreated($this->idSite)) {
+            Fixture::createWebsite('2014-01-02 03:04:05');
+        }
+        $this->trackData();
+    }
+
+    private function trackData()
+    {
+        $t = self::getTracker($this->idSite, $this->dateTime, $defaultInit = true);
+        self::checkResponse($t->doTrackPageView('Valid Site'));
+
+        $t = self::getTracker(99999, Date::now()->getDatetime(), $defaultInit = true);
+
+        for ($i = 0; $i < 2; $i++) {
+            // we trigger it multiple times to test it will be inserted only once
+            $t->doTrackPageView('Invalid Site');
+        }
+
+        $t = self::getTracker($this->idSite, $this->dateTime, $defaultInit = true);
+        $t->setIp('10.11.12.13');
+        $t->setTokenAuth('foobar'); //  wrong token
+        $t->doTrackPageView('Invalid Token');
+    }
+}
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/tests/Fixtures/SimpleFixtureTrackFewVisits.php b/plugins/CoreAdminHome/tests/Fixtures/SimpleFixtureTrackFewVisits.php
new file mode 100644
index 0000000000..b5c7fcf711
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/Fixtures/SimpleFixtureTrackFewVisits.php
@@ -0,0 +1,77 @@
+<?php
+/**
+ * Piwik - free/libre analytics platform
+ *
+ * @link    http://piwik.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+namespace Piwik\Plugins\CoreAdminHome\tests\Fixtures;
+
+use Piwik\Date;
+use Piwik\Tests\Framework\Fixture;
+
+/**
+ * Generates tracker testing data for our TrackingFailuresTest
+ *
+ * This Simple fixture adds one website and tracks one visit with couple pageviews and an ecommerce conversion
+ */
+class SimpleFixtureTrackFewVisits extends Fixture
+{
+    public $dateTime = '2013-01-23 01:23:45';
+    public $idSite = 1;
+
+    public function setUp()
+    {
+        $this->setUpWebsite();
+        $this->trackFirstVisit();
+        $this->trackSecondVisit();
+    }
+
+    public function tearDown()
+    {
+        // empty
+    }
+
+    private function setUpWebsite()
+    {
+        if (!self::siteCreated($this->idSite)) {
+            $idSite = self::createWebsite($this->dateTime, $ecommerce = 1);
+            $this->assertSame($this->idSite, $idSite);
+        }
+    }
+
+    protected function trackFirstVisit()
+    {
+        $t = self::getTracker($this->idSite, $this->dateTime, $defaultInit = true);
+
+        $t->setForceVisitDateTime(Date::factory($this->dateTime)->addHour(0.1)->getDatetime());
+        $t->setUrl('http://example.com/');
+        self::checkResponse($t->doTrackPageView('Viewing homepage'));
+
+        $t->setForceVisitDateTime(Date::factory($this->dateTime)->addHour(0.2)->getDatetime());
+        $t->setUrl('http://example.com/sub/page');
+        self::checkResponse($t->doTrackPageView('Second page view'));
+
+        $t->setForceVisitDateTime(Date::factory($this->dateTime)->addHour(0.25)->getDatetime());
+        $t->addEcommerceItem($sku = 'SKU_ID', $name = 'Test item!', $category = 'Test & Category', $price = 777, $quantity = 33);
+        self::checkResponse($t->doTrackEcommerceOrder('TestingOrder', $grandTotal = 33 * 77));
+    }
+
+    protected function trackSecondVisit()
+    {
+        $t = self::getTracker($this->idSite, $this->dateTime, $defaultInit = true);
+        $t->setIp('56.11.55.73');
+
+        $t->setForceVisitDateTime(Date::factory($this->dateTime)->addHour(0.1)->getDatetime());
+        $t->setUrl('http://example.com/sub/page');
+        self::checkResponse($t->doTrackPageView('Viewing homepage'));
+
+        $t->setForceVisitDateTime(Date::factory($this->dateTime)->addHour(0.2)->getDatetime());
+        $t->setUrl('http://example.com/?search=this is a site search query');
+        self::checkResponse($t->doTrackPageView('Site search query'));
+
+        $t->setForceVisitDateTime(Date::factory($this->dateTime)->addHour(0.3)->getDatetime());
+        $t->addEcommerceItem($sku = 'SKU_ID2', $name = 'A durable item', $category = 'Best seller', $price = 321);
+        self::checkResponse($t->doTrackEcommerceCartUpdate($grandTotal = 33 * 77));
+    }
+}
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/tests/Integration/APITest.php b/plugins/CoreAdminHome/tests/Integration/APITest.php
new file mode 100644
index 0000000000..a3ddf2a182
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/Integration/APITest.php
@@ -0,0 +1,134 @@
+<?php
+/**
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\CoreAdminHome\tests\Integration;
+
+use Piwik\Plugins\CoreAdminHome\API;
+use Piwik\Tests\Framework\Fixture;
+use Piwik\Tests\Framework\Mock\FakeAccess;
+
+/**
+ * @group CoreAdminHome
+ * @group APITest
+ * @group API
+ * @group Plugins
+ */
+class APITest extends \Piwik\Tests\Framework\TestCase\IntegrationTestCase
+{
+    /**
+     * @var int
+     */
+    private $idSite;
+
+    /**
+     * @var API
+     */
+    private $api;
+
+    public function setUp()
+    {
+        parent::setUp();
+        $this->api = API::getInstance();
+        for ($i = 0; $i < 5; $i++) {
+            Fixture::createWebsite('2014-01-02 03:04:05');
+        }
+    }
+
+    /**
+     * @expectedException \Piwik\NoAccessException
+     * @expectedExceptionMessage checkUserHasSomeAdminAccess
+     */
+    public function test_getTrackingFailures_failsForViewUser()
+    {
+        $this->setUser();
+        $this->api->getTrackingFailures();
+    }
+
+    public function test_getTrackingFailures_WorksForAdminAndSuperuser()
+    {
+        $this->setAdminUser();
+        $this->assertSame(array(), $this->api->getTrackingFailures());
+        $this->setSuperUser();
+        $this->api->getTrackingFailures();
+        $this->assertSame(array(), $this->api->getTrackingFailures());
+    }
+
+    /**
+     * @expectedException \Piwik\NoAccessException
+     * @expectedExceptionMessage checkUserHasSomeAdminAccess
+     */
+    public function test_deleteAllTrackingFailures_failsForViewUser()
+    {
+        $this->setUser();
+        $this->api->deleteAllTrackingFailures();
+    }
+
+    public function test_deleteAllTrackingFailures_WorksForAdminAndSuperuser()
+    {
+        $this->setAdminUser();
+        $this->api->deleteAllTrackingFailures();
+        $this->setSuperUser();
+        $this->api->deleteAllTrackingFailures();
+    }
+
+    /**
+     * @expectedException \Piwik\NoAccessException
+     * @expectedExceptionMessage checkUserHasAdminAccess
+     */
+    public function test_deleteTrackingFailure_failsForViewUser()
+    {
+        $this->setUser();
+        $this->api->deleteTrackingFailure(1, 2);
+    }
+
+    /**
+     * @expectedException \Piwik\NoAccessException
+     * @expectedExceptionMessage checkUserHasAdminAccess
+     */
+    public function test_deleteTrackingFailure_failsForAdminUserIfNotAdminAccessToThatSite()
+    {
+        $this->setAdminUser();
+        $this->api->deleteTrackingFailure(2, 2);
+    }
+
+    public function test_deleteTrackingFailure_WorksForAdminAndSuperuser()
+    {
+        $this->setAdminUser();
+        $this->api->deleteTrackingFailure(1, 2);
+        $this->setSuperUser();
+        $this->api->deleteTrackingFailure(1, 2);
+    }
+
+    protected function setSuperUser()
+    {
+        FakeAccess::clearAccess(true);
+    }
+
+    protected function setUser()
+    {
+        FakeAccess::clearAccess(false);
+        FakeAccess::$identity = 'testUser';
+        FakeAccess::$idSitesView = array(1,3, $this->idSite);
+        FakeAccess::$idSitesAdmin = array();
+    }
+
+    protected function setAdminUser()
+    {
+        FakeAccess::clearAccess(false);
+        FakeAccess::$identity = 'testUser';
+        FakeAccess::$idSitesView = array();
+        FakeAccess::$idSitesAdmin = array(1,3, $this->idSite);
+    }
+
+    public function provideContainerConfig()
+    {
+        return array(
+            'Piwik\Access' => new FakeAccess()
+        );
+    }
+}
diff --git a/plugins/CoreAdminHome/tests/Integration/TasksTest.php b/plugins/CoreAdminHome/tests/Integration/TasksTest.php
index d3ffc66518..ffab94c01d 100644
--- a/plugins/CoreAdminHome/tests/Integration/TasksTest.php
+++ b/plugins/CoreAdminHome/tests/Integration/TasksTest.php
@@ -14,12 +14,15 @@ use Piwik\Date;
 use Piwik\Db;
 use Piwik\Mail;
 use Piwik\Plugins\CoreAdminHome\Emails\JsTrackingCodeMissingEmail;
+use Piwik\Plugins\CoreAdminHome\Emails\TrackingFailuresEmail;
 use Piwik\Plugins\CoreAdminHome\Tasks;
 use Piwik\Plugins\CoreAdminHome\Tasks\ArchivesToPurgeDistributedList;
 use Piwik\Scheduler\Task;
 use Piwik\Tests\Fixtures\RawArchiveDataWithTempAndInvalidated;
 use Piwik\Tests\Framework\Fixture;
 use Piwik\Tests\Framework\TestCase\IntegrationTestCase;
+use Piwik\Tracker\Failures;
+use Piwik\Tracker\Request;
 use Psr\Log\NullLogger;
 
 /**
@@ -66,7 +69,7 @@ class TasksTest extends IntegrationTestCase
         $archivePurger->setYesterdayDate(Date::factory('2015-02-26'));
         $archivePurger->setNow(Date::factory('2015-02-27 08:00:00')->getTimestamp());
 
-        $this->tasks = new Tasks($archivePurger, new NullLogger());
+        $this->tasks = new Tasks($archivePurger, new NullLogger(), new Failures());
 
         $this->mail = null;
     }
@@ -129,6 +132,8 @@ class TasksTest extends IntegrationTestCase
             'purgeOutdatedArchives.',
             'purgeInvalidatedArchives.',
             'optimizeArchiveTable.',
+            'cleanupTrackingFailures.',
+            'notifyTrackingFailures.',
             'updateSpammerBlacklist.',
             'checkSiteHasTrackedVisits.2',
             'checkSiteHasTrackedVisits.3',
@@ -181,6 +186,35 @@ class TasksTest extends IntegrationTestCase
         $this->assertEquals($mail->getIdSite(), $idSite);
     }
 
+    public function test_cleanupTrackingFailures_doesNotCauseAnyException()
+    {
+        // it is only calling one method which is already tested... no need to write complex tests for it
+        $this->tasks->cleanupTrackingFailures();
+        $this->assertTrue(true);
+    }
+
+    public function test_notifyTrackingFailures_doesNotSendAnyMailWhenThereAreNoTrackingRequests()
+    {
+        $this->tasks->notifyTrackingFailures();
+        $this->assertNull($this->mail);
+    }
+
+    public function test_notifyTrackingFailures_sendsMailWhenThereAreTrackingFailures()
+    {
+        $failures = new Failures();
+        $failures->logFailure(1, new Request(array('idsite' => 9999, 'rec' => 1)));
+        $failures->logFailure(1, new Request(array('idsite' => 9998, 'rec' => 1)));
+        Fixture::createSuperUser(false);
+        $this->tasks->notifyTrackingFailures();
+
+        /** @var TrackingFailuresEmail $mail */
+        $mail = $this->mail;
+        $this->assertInstanceOf(TrackingFailuresEmail::class, $mail);
+        $this->assertEquals('superUserLogin', $mail->getLogin());
+        $this->assertEquals('hello@example.org', $mail->getEmailAddress());
+        $this->assertEquals(2, $mail->getNumFailures());
+    }
+
     /**
      * @param Date[] $dates
      */
diff --git a/plugins/CoreAdminHome/tests/System/TrackingFailuresTest.php b/plugins/CoreAdminHome/tests/System/TrackingFailuresTest.php
new file mode 100644
index 0000000000..061c819e60
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/System/TrackingFailuresTest.php
@@ -0,0 +1,63 @@
+<?php
+/**
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+namespace Piwik\Plugins\CoreAdminHome\tests\System;
+
+use Piwik\Plugins\CoreAdminHome\tests\Fixture\TrackingFailures;
+use Piwik\Tests\Framework\TestCase\SystemTestCase;
+
+/**
+ * @group CoreAdminHome
+ * @group TrackingFailuresTest
+ * @group Plugins
+ */
+class TrackingFailuresTest extends SystemTestCase
+{
+    /**
+     * @var TrackingFailures
+     */
+    public static $fixture = null; // initialized below class definition
+
+    /**
+     * @dataProvider getApiForTesting
+     */
+    public function testApi($api, $params)
+    {
+        $params['xmlFieldsToRemove'] = array('date_first_occurred', 'pretty_date_first_occurred', 'request_url');
+        $this->runApiTests($api, $params);
+    }
+
+    public function getApiForTesting()
+    {
+        $api = array(
+            'CoreAdminHome.getTrackingFailures',
+        );
+
+        $apiToTest   = array();
+        $apiToTest[] = array($api,
+            array(
+                'testSuffix' => ''
+            )
+        );
+
+        return $apiToTest;
+    }
+
+    public static function getOutputPrefix()
+    {
+        return '';
+    }
+
+    public static function getPathToTestDirectory()
+    {
+        return dirname(__FILE__);
+    }
+
+}
+
+TrackingFailuresTest::$fixture = new TrackingFailures();
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/tests/System/expected/test___CoreAdminHome.getTrackingFailures.xml b/plugins/CoreAdminHome/tests/System/expected/test___CoreAdminHome.getTrackingFailures.xml
new file mode 100644
index 0000000000..511339901f
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/System/expected/test___CoreAdminHome.getTrackingFailures.xml
@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<result>
+	<row>
+		<idsite>1</idsite>
+		<idfailure>2</idfailure>
+		
+		
+		<site_name>Piwik test</site_name>
+		
+		<url>http://example.com/piwik/</url>
+		<problem>Request was not authenticated but authentication was required.</problem>
+		<solution>Set or correct a &quot;token_auth&quot; in your tracking request.</solution>
+		<solution_url>https://matomo.org/faq/how-to/faq_30835/</solution_url>
+	</row>
+	<row>
+		<idsite>99999</idsite>
+		<idfailure>1</idfailure>
+		
+		
+		<site_name>Unknown</site_name>
+		
+		<url>http://example.com/piwik/</url>
+		<problem>The site does not exist.</problem>
+		<solution>Update the configured idSite in the tracker.</solution>
+		<solution_url>https://matomo.org/faq/how-to/faq_30838/</solution_url>
+	</row>
+</result>
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/tests/UI/TrackingFailures_spec.js b/plugins/CoreAdminHome/tests/UI/TrackingFailures_spec.js
new file mode 100644
index 0000000000..f98f1c0646
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/TrackingFailures_spec.js
@@ -0,0 +1,94 @@
+/*!
+ * Matomo - free/libre analytics platform
+ *
+ * @link https://matomo.org
+ * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
+ */
+
+describe("TrackingFailures", function () {
+    this.timeout(0);
+
+    var manageUrl = '?module=CoreAdminHome&action=trackingFailures&idSite=1&period=day&date=today';
+    var widgetUrl = '?module=Widgetize&action=iframe&moduleToWidgetize=CoreAdminHome&actionToWidgetize=getTrackingFailures&idSite=1&period=day&date=today&widget=1';
+
+    function captureScreen(done, screenshotName, theTest)
+    {
+        expect.screenshot(screenshotName).to.be.captureSelector('.matomoTrackingFailures', theTest, done);
+    }
+
+    function captureModal(done, screenshotName, theTest)
+    {
+        expect.screenshot(screenshotName).to.be.captureSelector('.modal.open', theTest, done);
+    }
+
+    function generateTrackingFailures()
+    {
+        testEnvironment.generateTrackingFailures = 1;
+        testEnvironment.save();
+    }
+
+    function confirmModal(page)
+    {
+        page.click('.modal.open .modal-footer a:contains(Yes)');
+    }
+
+    afterEach(function () {
+        delete testEnvironment.generateTrackingFailures;
+        testEnvironment.save();
+    });
+
+    it('should show widget with no failures', function (done) {
+        captureScreen(done, 'widget_no_failures', function (page) {
+            page.load(widgetUrl);
+        });
+    });
+
+    it('should show manage page with no failures', function (done) {
+        captureScreen(done, 'manage_no_failures', function (page) {
+            page.load(manageUrl);
+        });
+    });
+
+    it('should show widget with failures', function (done) {
+        generateTrackingFailures();
+        captureScreen(done, 'widget_with_failures', function (page) {
+            generateTrackingFailures();
+            page.load(widgetUrl);
+        });
+    });
+
+    it('should show manage page with failures', function (done) {
+        generateTrackingFailures();
+        captureScreen(done, 'manage_with_failures', function (page) {
+            generateTrackingFailures();
+            page.load(manageUrl);
+        });
+    });
+
+    it('should show ask to confirm delete one', function (done) {
+        captureModal(done, 'manage_with_failures_delete_one_ask_confirmation', function (page) {
+            page.evaluate(function () {
+                $('.matomoTrackingFailures table tbody tr:nth-child(2) .icon-delete').click()
+            });
+        });
+    });
+
+    it('should show delete when confirmed', function (done) {
+        captureScreen(done, 'manage_with_failures_delete_one_confirmed', function (page) {
+            confirmModal(page);
+        });
+    });
+
+    it('should show ask to confirm delete all', function (done) {
+        captureModal(done, 'manage_with_failures_delete_all_ask_confirmation', function (page) {
+            page.click('.matomoTrackingFailures .deleteAllFailures');
+        });
+    });
+
+    it('should show ask to confirm delete one', function (done) {
+        captureScreen(done, 'manage_with_failures_delete_all_confirmed', function (page) {
+            confirmModal(page);
+        });
+    });
+
+});
\ No newline at end of file
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_no_failures.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_no_failures.png
new file mode 100644
index 0000000000..3652d932ca
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_no_failures.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:555956386a3960079e98fd0ed955ccf836d5aef1e9883f330ef08e43c496f3ff
+size 25706
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures.png
new file mode 100644
index 0000000000..3920b896ea
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:164fc892e74d90ff316f76cc424dbb00e8af9f8ff5c487deaca4df67fb3b058d
+size 75105
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_all_ask_confirmation.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_all_ask_confirmation.png
new file mode 100644
index 0000000000..d087655199
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_all_ask_confirmation.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:7a8c736bf8efa2dde7c14609ae473fddd4c09f616cbfa1d794bddcc01d12b707
+size 9554
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_all_confirmed.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_all_confirmed.png
new file mode 100644
index 0000000000..3652d932ca
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_all_confirmed.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:555956386a3960079e98fd0ed955ccf836d5aef1e9883f330ef08e43c496f3ff
+size 25706
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_one_ask_confirmation.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_one_ask_confirmation.png
new file mode 100644
index 0000000000..372005bf86
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_one_ask_confirmation.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:3a773a094fe4a81c031a71ad279ccda03cee6f3b8139ed6bbaac27c6ea8ff7c4
+size 9585
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_one_confirmed.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_one_confirmed.png
new file mode 100644
index 0000000000..237b4c9a7a
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_manage_with_failures_delete_one_confirmed.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:32619750eb571199b8fb5b0761efe64d46f9db3dd090b7f8bbc7a1151aa5e295
+size 48513
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_widget_no_failures.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_widget_no_failures.png
new file mode 100644
index 0000000000..c610efccb2
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_widget_no_failures.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:8151ae81cc83466e763346f02b272dc7ec480832d49807f59cfb32a53630da6a
+size 11165
diff --git a/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_widget_with_failures.png b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_widget_with_failures.png
new file mode 100644
index 0000000000..fc40fbe9b1
--- /dev/null
+++ b/plugins/CoreAdminHome/tests/UI/expected-screenshots/TrackingFailures_widget_with_failures.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1a98049c33bb5cab09436985b5cf062a931560028014f8c9f8b1ccc0d50c3af8
+size 12805
diff --git a/plugins/CoreHome/CoreHome.php b/plugins/CoreHome/CoreHome.php
index 76e933ae51..ab11a468eb 100644
--- a/plugins/CoreHome/CoreHome.php
+++ b/plugins/CoreHome/CoreHome.php
@@ -287,6 +287,8 @@ class CoreHome extends \Piwik\Plugin
         $jsFiles[] = "plugins/CoreAdminHome/angularjs/trackingcode/jstrackingcode.controller.js";
         $jsFiles[] = "plugins/CoreAdminHome/angularjs/trackingcode/imagetrackingcode.controller.js";
         $jsFiles[] = "plugins/CoreAdminHome/angularjs/archiving/archiving.controller.js";
+        $jsFiles[] = "plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.controller.js";
+        $jsFiles[] = "plugins/CoreAdminHome/angularjs/trackingfailures/trackingfailures.directive.js";
 
         // we have to load these CorePluginsAdmin files here. If we loaded them in CorePluginsAdmin,
         // there would be JS errors as CorePluginsAdmin is loaded first. Meaning it is loaded before
diff --git a/plugins/CoreHome/Tracker/VisitRequestProcessor.php b/plugins/CoreHome/Tracker/VisitRequestProcessor.php
index 033399e196..c2a88e93d4 100644
--- a/plugins/CoreHome/Tracker/VisitRequestProcessor.php
+++ b/plugins/CoreHome/Tracker/VisitRequestProcessor.php
@@ -88,7 +88,10 @@ class VisitRequestProcessor extends RequestProcessor
         $visitProperties->setProperty('location_ip', $request->getIp());
 
         $excluded = new VisitExcluded($request);
-        if ($excluded->isExcluded()) {
+        $isExcluded = $excluded->isExcluded();
+        $request->setMetadata('CoreHome', 'isVisitExcluded', $isExcluded);
+
+        if ($isExcluded) {
             return true;
         }
 
diff --git a/plugins/CustomVariables/tests/UI/expected-screenshots/CustomVariables_link_in_menu.png b/plugins/CustomVariables/tests/UI/expected-screenshots/CustomVariables_link_in_menu.png
index 62e1cb3583..ea9a6fe395 100644
--- a/plugins/CustomVariables/tests/UI/expected-screenshots/CustomVariables_link_in_menu.png
+++ b/plugins/CustomVariables/tests/UI/expected-screenshots/CustomVariables_link_in_menu.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:08217344adea43733531372ee479b5f11dc6f67d7ac40f07284e8feaae5b3c8a
-size 14959
+oid sha256:f7798c4e443bd838de905511c77f82899e44d4d2e990e5623ee2fd0b2a09c79d
+size 16695
diff --git a/plugins/QueuedTracking b/plugins/QueuedTracking
-Subproject 49e30794fcf0a77bac7cef9e5c779e855453549
+Subproject 7609e1bd46b5da8f8e638c01dc71fb782dffdb9
diff --git a/plugins/SitesManager/SitesManager.php b/plugins/SitesManager/SitesManager.php
index 76576f84ed..054ecc2fce 100644
--- a/plugins/SitesManager/SitesManager.php
+++ b/plugins/SitesManager/SitesManager.php
@@ -8,9 +8,11 @@
  */
 namespace Piwik\Plugins\SitesManager;
 
+use Piwik\Access;
 use Piwik\API\Request;
 use Piwik\Common;
 use Piwik\Container\StaticContainer;
+use Piwik\Exception\UnexpectedWebsiteFoundException;
 use Piwik\Piwik;
 use Piwik\Plugins\CoreHome\SystemSummary;
 use Piwik\Plugins\PrivacyManager\PrivacyManager;
@@ -36,7 +38,8 @@ class SitesManager extends \Piwik\Plugin
         return array(
             'AssetManager.getJavaScriptFiles'        => 'getJsFiles',
             'AssetManager.getStylesheetFiles'        => 'getStylesheetFiles',
-            'Tracker.Cache.getSiteAttributes'        => 'recordWebsiteDataInCache',
+            'Tracker.Cache.getSiteAttributes'        => array('function' => 'recordWebsiteDataInCache', 'before' => true),
+            'Tracker.setTrackerCacheGeneral'         => 'setTrackerCacheGeneral',
             'Translate.getClientSideTranslationKeys' => 'getClientSideTranslationKeys',
             'SitesManager.deleteSite.end'            => 'onSiteDeleted',
             'System.addSystemSummaryItems'           => 'addSystemSummaryItems',
@@ -145,13 +148,13 @@ class SitesManager extends \Piwik\Plugin
     {
         $idSite = (int) $idSite;
 
+        $website = API::getInstance()->getSiteFromId($idSite);
         $urls = API::getInstance()->getSiteUrlsFromId($idSite);
 
         // add the 'hosts' entry in the website array
         $array['urls']  = $urls;
         $array['hosts'] = $this->getTrackerHosts($urls);
 
-        $website = API::getInstance()->getSiteFromId($idSite);
         $array['exclude_unknown_urls'] = $website['exclude_unknown_urls'];
         $array['excluded_ips'] = $this->getTrackerExcludedIps($website);
         $array['excluded_parameters'] = self::getTrackerExcludedQueryParameters($website);
@@ -165,6 +168,14 @@ class SitesManager extends \Piwik\Plugin
         $array['type'] = $website['type'];
     }
 
+    public function setTrackerCacheGeneral(&$cache)
+    {
+        Access::doAsSuperUser(function () use (&$cache) {
+            $cache['global_excluded_user_agents'] = self::filterBlankFromCommaSepList(API::getInstance()->getExcludedUserAgentsGlobal());
+            $cache['global_excluded_ips'] = self::filterBlankFromCommaSepList(API::getInstance()->getExcludedIpsGlobal());
+        });
+    }
+
     /**
      * Returns whether we should keep URL fragments for a specific site.
      *
diff --git a/plugins/Widgetize/tests/System/WidgetTest.php b/plugins/Widgetize/tests/System/WidgetTest.php
index cdf8fe54ff..96b78dd70b 100644
--- a/plugins/Widgetize/tests/System/WidgetTest.php
+++ b/plugins/Widgetize/tests/System/WidgetTest.php
@@ -1016,6 +1016,14 @@ class WidgetTest extends SystemTestCase
                         'action' => 'getSystemCheck',
                     ),
             ), array (
+                'name' => 'Tracking failures',
+                'uniqueId' => 'widgetCoreAdminHomegetTrackingFailures',
+                'parameters' =>
+                    array (
+                        'module' => 'CoreAdminHome',
+                        'action' => 'getTrackingFailures',
+                    ),
+            ), array (
                 'name' => 'System Summary',
                 'uniqueId' => 'widgetCoreHomegetSystemSummary',
                 'parameters' =>