Fatal error: Uncaught Error: Interface "League\Config\ConfigurationInterface" not found in /opt/lampp/htdocs/forum/flarum/vendor/league/config/src/ReadOnlyConfiguration.php:19 Stack trace: #0 {main} thrown in /opt/lampp/htdocs/forum/flarum/vendor/league/config/src/ReadOnlyConfiguration.php on line 19