Fatal error: Uncaught Error: Interface "Psr\Http\Server\MiddlewareInterface" not found in /home/rcmch/test.m-s-i.ch/vendor/typo3/cms-backend/Classes/Middleware/BackendModuleValidator.php:48 Stack trace: #0 {main} thrown in /home/rcmch/test.m-s-i.ch/vendor/typo3/cms-backend/Classes/Middleware/BackendModuleValidator.php on line 48