Fatal error: Uncaught Error: Interface "Psr\EventDispatcher\StoppableEventInterface" not found in /var/www/html/dev.hallescherfc.de/vendor/extcode/cart/Classes/Event/Mail/AttachmentEvent.php:10 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/vendor/extcode/cart/Classes/Event/Mail/AttachmentEvent.php on line 10