Fatal error: Uncaught Error: Interface 'Symfony\Component\Serializer\SerializerInterface' not found in /home/devmecseminars/public_html/mec/vendor/symfony/serializer/Serializer.php:47 Stack trace: #0 {main} thrown in /home/devmecseminars/public_html/mec/vendor/symfony/serializer/Serializer.php on line 47