Fatal error: Uncaught Error: Class "Symfony\Component\EventDispatcher\Event" not found in /users/ms-it/www/oc/lib/composer/symfony/event-dispatcher/LegacyEventProxy.php:20 Stack trace: #0 {main} thrown in /users/ms-it/www/oc/lib/composer/symfony/event-dispatcher/LegacyEventProxy.php on line 20