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/ec3d395a453221117ba86dbe4a7b5b868d5a00e4/examples/FormantShifter_FD_OA You should set ROOT_URL correctly, otherwise the web may not work correctly.