Fatal error: Uncaught Error: Class "Symfony\Contracts\EventDispatcher\Event" not found in /home/flighto/e-commerce/vendor/sonata-project/block-bundle/src/Event/BlockEvent.php:19 Stack trace: #0 {main} thrown in /home/flighto/e-commerce/vendor/sonata-project/block-bundle/src/Event/BlockEvent.php on line 19