Fatal error: Uncaught Error: Class 'Symfony\Component\Templating\Helper\Helper' not found in /home/users/00/3c/21/home/www/vendor/jms/serializer-bundle/Templating/SerializerHelper.php:15 Stack trace: #0 {main} thrown in /home/users/00/3c/21/home/www/vendor/jms/serializer-bundle/Templating/SerializerHelper.php on line 15