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/1d39ef16ef12ac4d723ac9bb1fe39b2dcc9508a5/examples/TestConvolutinalFilter You should set ROOT_URL correctly, otherwise the web may not work correctly.