Fatal error: Uncaught Error: Class "ApiPlatform\Metadata\GraphQl\Operation" not found in /var/www/html/API_Forum/vendor/api-platform/metadata/GraphQl/Subscription.php:20 Stack trace: #0 {main} thrown in /var/www/html/API_Forum/vendor/api-platform/metadata/GraphQl/Subscription.php on line 20