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/94a4069f0df8800f344da44226eab2641bf6a4c4/examples/TestInputOutput_float You should set ROOT_URL correctly, otherwise the web may not work correctly.