Fatal error: Uncaught Error: Class "Symfony\Component\Serializer\Mapping\Loader\FileLoader" not found in D:\Webserver\Apache24\htdocs\testephp\signxml\vendor\symfony\serializer\Mapping\Loader\YamlFileLoader.php:28 Stack trace: #0 {main} thrown in D:\Webserver\Apache24\htdocs\testephp\signxml\vendor\symfony\serializer\Mapping\Loader\YamlFileLoader.php on line 28