Fatal error: Uncaught Error: Class "Symfony\Contracts\EventDispatcher\Event" not found in C:\xampp\htdocs\adminlte3\vendor\symfony\http-kernel\Event 2\KernelEvent.php:23 Stack trace: #0 {main} thrown in C:\xampp\htdocs\adminlte3\vendor\symfony\http-kernel\Event 2\KernelEvent.php on line 23