Fatal error: Uncaught TYPO3\CMS\Extbase\Property\Exception\InvalidSourceException: The identity property "grab" is no UID. in /usr/www/users/steink/typo3_src-7.6.32/typo3/sysext/extbase/Classes/Property/TypeConverter/PersistentObjectConverter.php:219 Stack trace: #0 /usr/www/users/steink/typo3_src-7.6.32/typo3/sysext/extbase/Classes/Property/TypeConverter/PersistentObjectConverter.php(158): TYPO3\CMS\Extbase\Property\TypeConverter\PersistentObjectConverter->fetchObjectFromPersistence('grab', 'Projekte\\Projek...') #1 /usr/www/users/steink/typo3_src-7.6.32/typo3/sysext/extbase/Classes/Property/PropertyMapper.php(199): TYPO3\CMS\Extbase\Property\TypeConverter\PersistentObjectConverter->convertFrom('grab', 'Projekte\\Projek...', Array, Object(TYPO3\CMS\Extbase\Mvc\Controller\MvcPropertyMappingConfiguration)) #2 /usr/www/users/steink/typo3_src-7.6.32/typo3/sysext/extbase/Classes/Property/PropertyMapper.php(119): TYPO3\CMS\Extbase\Property\PropertyMapper->doMapping('grab', 'Projekte\\Projek...', Object(TYPO3\CMS\Extbase\Mvc\Co in /usr/www/users/steink/typo3_src-7.6.32/typo3/sysext/extbase/Classes/Property/PropertyMapper.php on line 128