Fatal error: Uncaught Error: Class "Symfony\Contracts\EventDispatcher\Event" not found in D:\Apache24\www\qilu_sap\back-end\vendor\symfony\mailer\Event\FailedMessageEvent.php:20 Stack trace: #0 {main} thrown in D:\Apache24\www\qilu_sap\back-end\vendor\symfony\mailer\Event\FailedMessageEvent.php on line 20