Fatal error: Uncaught Error: Interface "Tobscure\JsonApi\SerializerInterface" not found in /opt/lampp/htdocs/forum/flarum/vendor/sycho/json-api/src/AbstractSerializer.php:16 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/forum/flarum/vendor/sycho/json-api/src/AbstractSerializer.php on line 16