Fatal error: Uncaught Error: Class 'Symfony\Component\HttpKernel\EventListener\AbstractSessionListener' not found in /home/app/htdocs/message_gateway/vendor/symfony/http-kernel/EventListener/SessionListener.php:23 Stack trace: #0 {main} thrown in /home/app/htdocs/message_gateway/vendor/symfony/http-kernel/EventListener/SessionListener.php on line 23