Fatal error: Uncaught Error: Interface "Symfony\Component\Serializer\SerializerInterface" not found in D:\Webserver\Apache24\htdocs\testephp\signxml\vendor\symfony\serializer\Serializer.php:46 Stack trace: #0 {main} thrown in D:\Webserver\Apache24\htdocs\testephp\signxml\vendor\symfony\serializer\Serializer.php on line 46