Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/OpenAudio_ArduinoLibrary/src/commit/81492cc5aca290d95cd6b681729302148cb7e109/docs/font-awesome
You should set ROOT_URL correctly, otherwise the web may not work correctly.