Fatal error: Uncaught Error: Class "Symfony\Component\Serializer\Normalizer\AbstractNormalizer" not found in /srv/disk3/2724534/www/transdoetaskforce.org/concrete/vendor/symfony/serializer/Normalizer/AbstractObjectNormalizer.php:37 Stack trace: #0 {main} thrown in /srv/disk3/2724534/www/transdoetaskforce.org/concrete/vendor/symfony/serializer/Normalizer/AbstractObjectNormalizer.php on line 37