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/2e7df3af345678a6774a2c9465c8aaf41f7ee43c/examples/ToneDetect1 You should set ROOT_URL correctly, otherwise the web may not work correctly.