Fatal error: Uncaught Error: Class "Symfony\Component\EventDispatcher\Event" not found in /var/www/apache/dev/cal/web/vendor/symfony/security/Http/Event/SwitchUserEvent.php:23 Stack trace: #0 {main} thrown in /var/www/apache/dev/cal/web/vendor/symfony/security/Http/Event/SwitchUserEvent.php on line 23