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/426413a1695a7c51384790d08b3606ac82eedc23/docs/jquery/css/smoothness/images You should set ROOT_URL correctly, otherwise the web may not work correctly.