Fatal error: Uncaught Error: Class 'Symfony\Component\Notifier\Channel\AbstractChannel' not found in /home/benjamincb/demos/acdg/vendor/symfony/notifier/Channel/ChatChannel.php:22 Stack trace: #0 {main} thrown in /home/benjamincb/demos/acdg/vendor/symfony/notifier/Channel/ChatChannel.php on line 22