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/a609fa8602e9e81d45369c8d5307af6761b81366/docs/font-awesome
You should set ROOT_URL correctly, otherwise the web may not work correctly.