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/675f5283ca091cad512c4a908518c19259ea8bcb/examples/FFTFrequencyMeter
You should set ROOT_URL correctly, otherwise the web may not work correctly.
boblark