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/3319cfa8cb8c938e0d9b4d41ff17143d96832dd2/docs/jquery/css/smoothness/images You should set ROOT_URL correctly, otherwise the web may not work correctly.