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/817b33e2d67ae330d4e74c7ded81b5812de5f02e/examples/AudioTestPeakRMS You should set ROOT_URL correctly, otherwise the web may not work correctly.