Fatal error: Uncaught Error: Interface "Psr\EventDispatcher\EventDispatcherInterface" not found in /home/homepaa/www/classic-Vorlage/vendor/symfony/event-dispatcher-contracts/EventDispatcherInterface.php:19 Stack trace: #0 {main} thrown in /home/homepaa/www/classic-Vorlage/vendor/symfony/event-dispatcher-contracts/EventDispatcherInterface.php on line 19