Fatal error: Uncaught Error: Interface "TYPO3\CMS\Core\SingletonInterface" not found in /var/www/html/v12.hallescherfc.de/vendor/typo3/cms-core/Classes/Page/AssetCollector.php:41 Stack trace: #0 {main} thrown in /var/www/html/v12.hallescherfc.de/vendor/typo3/cms-core/Classes/Page/AssetCollector.php on line 41