Fatal error: Uncaught Error: Interface "Symfony\Component\HttpFoundation\Session\Flash\FlashBagInterface" not found in /var/www/apache/dev/cal/web/vendor/symfony/http-foundation/Session/Flash/FlashBag.php:21 Stack trace: #0 {main} thrown in /var/www/apache/dev/cal/web/vendor/symfony/http-foundation/Session/Flash/FlashBag.php on line 21