Fatal error: Uncaught Error: Class 'Symfony\Component\EventDispatcher\Event' not found in /home/itscm/dev.its.cm/webserivesits/vendor/friendsofsymfony/user-bundle/Event/GroupEvent.php:18 Stack trace: #0 {main} thrown in /home/itscm/dev.its.cm/webserivesits/vendor/friendsofsymfony/user-bundle/Event/GroupEvent.php on line 18