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/a35712c8abf595cab417ff0ec46f9d5be6c2dfa6/docs/bootstrap/css
You should set ROOT_URL correctly, otherwise the web may not work correctly.
Chip Audette