Fatal error: Uncaught Error: Class "Symfony\Component\DependencyInjection\Extension\Extension" not found in C:\wamp64\houda\vendor\symfony\http-kernel\DependencyInjection\ConfigurableExtension.php:29 Stack trace: #0 {main} thrown in C:\wamp64\houda\vendor\symfony\http-kernel\DependencyInjection\ConfigurableExtension.php on line 29