Fatal error: Uncaught Error: Class "Symfony\Component\Validator\ConstraintValidator" not found in /var/www/crm_killing_ninja/core/backend/MediaObjects/Validator/UploadValidator/UploadConstraintValidator.php:36 Stack trace: #0 {main} thrown in /var/www/crm_killing_ninja/core/backend/MediaObjects/Validator/UploadValidator/UploadConstraintValidator.php on line 36