Fatal error: Uncaught Error: Class "Masterminds\HTML5\Serializer\OutputRules" not found in /var/www/html/dev.hallescherfc.de/vendor/typo3/html-sanitizer/src/Serializer/Rules.php:26 Stack trace: #0 {main} thrown in /var/www/html/dev.hallescherfc.de/vendor/typo3/html-sanitizer/src/Serializer/Rules.php on line 26