Fatal error: Uncaught Error: Class "Symfony\Component\Serializer\Mapping\Loader\FileLoader" not found in I:\www\picman\vendor\symfony\serializer\Mapping\Loader\XmlFileLoader.php:27 Stack trace: #0 {main} thrown in I:\www\picman\vendor\symfony\serializer\Mapping\Loader\XmlFileLoader.php on line 27