Fatal error: Uncaught Error: Interface 'Symfony\Component\DependencyInjection\Extension\ExtensionInterface' not found in /home/devmecseminars/public_html/mec/vendor/symfony/dependency-injection/Extension/Extension.php:26 Stack trace: #0 {main} thrown in /home/devmecseminars/public_html/mec/vendor/symfony/dependency-injection/Extension/Extension.php on line 26