Fatal error: Uncaught Error: Class 'Symfony\Component\Serializer\Mapping\Loader\FileLoader' not found in /home/soh-works/www/3good_old/vendor/symfony/serializer/Mapping/Loader/YamlFileLoader.php:26 Stack trace: #0 {main} thrown in /home/soh-works/www/3good_old/vendor/symfony/serializer/Mapping/Loader/YamlFileLoader.php on line 26