Fatal error: Uncaught Error: Class "Symfony\Contracts\EventDispatcher\Event" not found in /opt/lampp/htdocs/forum/flarum/vendor/symfony/event-dispatcher/GenericEvent.php:26 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/forum/flarum/vendor/symfony/event-dispatcher/GenericEvent.php on line 26