Fatal error: Uncaught Error: Interface "Ratchet\ConnectionInterface" not found in /users/energydata/www/volkszaehler.org/vendor/cboden/ratchet/src/Ratchet/Server/IoConnection.php:9 Stack trace: #0 {main} thrown in /users/energydata/www/volkszaehler.org/vendor/cboden/ratchet/src/Ratchet/Server/IoConnection.php on line 9