Fatal error: Uncaught Error: Class 'Symfony\Component\EventDispatcher\Event' not found in /home/app/htdocs/message_gateway/vendor/symfony/event-dispatcher/LegacyEventProxy.php:20 Stack trace: #0 {main} thrown in /home/app/htdocs/message_gateway/vendor/symfony/event-dispatcher/LegacyEventProxy.php on line 20