Fatal error: Uncaught Error: Class "TYPO3\CMS\Extbase\Validation\Validator\AbstractValidator" not found in /var/www/html/v12.hallescherfc.de/packages/hfcmembership/Classes/Domain/Validator/HfcUsernameAvailableValidator.php:10 Stack trace: #0 {main} thrown in /var/www/html/v12.hallescherfc.de/packages/hfcmembership/Classes/Domain/Validator/HfcUsernameAvailableValidator.php on line 10