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/15b07452c22be78991e00dcd9fc80f0f463a2e75/examples/FrequencyShifter_FD_OA You should set ROOT_URL correctly, otherwise the web may not work correctly.