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/03c16e07d254095857bbdd94186ced4b5c4036b8/examples/testCompressor2 You should set ROOT_URL correctly, otherwise the web may not work correctly.