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/daf61a4d96d7f661afc63ff40271c5d272e4287d/docs/bootstrap/img
You should set ROOT_URL correctly, otherwise the web may not work correctly.