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/ce659515effbb17086409be04a5ab2a7595b4699/examples/MyAudioEffect_Float You should set ROOT_URL correctly, otherwise the web may not work correctly.