Fatal error: Uncaught Error: Interface 'Symfony\Component\HttpFoundation\Session\Flash\FlashBagInterface' not found in /mnt/volume_lon1_01/backend/admin/vendor/symfony/http-foundation/Session/Flash/FlashBag.php:19 Stack trace: #0 {main} thrown in /mnt/volume_lon1_01/backend/admin/vendor/symfony/http-foundation/Session/Flash/FlashBag.php on line 19