Fatal error: Uncaught Error: Class "Symfony\Component\EventDispatcher\Event" not found in /home/vincent/http/concrete5/concrete/vendor/symfony/http-kernel/Event/KernelEvent.php:23 Stack trace: #0 {main} thrown in /home/vincent/http/concrete5/concrete/vendor/symfony/http-kernel/Event/KernelEvent.php on line 23