Fatal error: Uncaught Error: Interface 'Symfony\Component\HttpFoundation\Session\Flash\FlashBagInterface' not found in /var/www/typo3/vendor/symfony/http-foundation/Session/Flash/FlashBag.php:19 Stack trace: #0 {main} thrown in /var/www/typo3/vendor/symfony/http-foundation/Session/Flash/FlashBag.php on line 19