Fatal error: Uncaught Error: Class "Symfony\Component\DependencyInjection\Extension\Extension" not found in /home/vincent/http/concrete5/concrete/vendor/symfony/http-kernel/DependencyInjection/Extension.php:21 Stack trace: #0 {main} thrown in /home/vincent/http/concrete5/concrete/vendor/symfony/http-kernel/DependencyInjection/Extension.php on line 21