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/d1955a2ce0b6b0a8ed0ef29d05dfd6f1b7a3d22d/examples/FFTFrequencyMeter
You should set ROOT_URL correctly, otherwise the web may not work correctly.
boblark