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/d095b21eb79a6cb496808b2c1af9a9651e7da107/examples/testCompressor2 You should set ROOT_URL correctly, otherwise the web may not work correctly.