Fatal error: Uncaught Error: Interface 'Sonata\NotificationBundle\Backend\BackendInterface' not found in /home/lafaamicps/www/symfony/vendor/sonata-project/notification-bundle/Backend/MessageManagerBackend.php:26 Stack trace: #0 {main} thrown in /home/lafaamicps/www/symfony/vendor/sonata-project/notification-bundle/Backend/MessageManagerBackend.php on line 26