Fatal error: Uncaught Error: Class "Symfony\Component\Serializer\Normalizer\AbstractObjectNormalizer" not found in /home/vincent/http/concrete5/concrete/vendor/symfony/serializer/Normalizer/PropertyNormalizer.php:31 Stack trace: #0 {main} thrown in /home/vincent/http/concrete5/concrete/vendor/symfony/serializer/Normalizer/PropertyNormalizer.php on line 31