Fatal error: Uncaught Error: Class 'Symfony\Component\HttpKernel\EventListener\AbstractSessionListener' not found in D:\xampp\htdocs\psp\backend\vendor\symfony\http-kernel\EventListener\SessionListener.php:29 Stack trace: #0 {main} thrown in D:\xampp\htdocs\psp\backend\vendor\symfony\http-kernel\EventListener\SessionListener.php on line 29