Fatal error: Uncaught Error: Class 'Symfony\Component\EventDispatcher\Event' not found in G:\projects\bot.edutalk.edu.vn\vendor\symfony\event-dispatcher\GenericEvent.php:21 Stack trace: #0 {main} thrown in G:\projects\bot.edutalk.edu.vn\vendor\symfony\event-dispatcher\GenericEvent.php on line 21