Fatal error: Uncaught Error: Interface "Symfony\Component\Serializer\Mapping\ClassDiscriminatorResolverInterface" not found in /home/akg/public_html/craft/vendor/symfony/serializer/Mapping/ClassDiscriminatorFromClassMetadata.php:19 Stack trace: #0 {main} thrown in /home/akg/public_html/craft/vendor/symfony/serializer/Mapping/ClassDiscriminatorFromClassMetadata.php on line 19