Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/AutoConnect/src/commit/c9450a100506d4c8487a77aefd0bf9b447b742e6/examples/mqttRSSI_FS
You should set ROOT_URL correctly, otherwise the web may not work correctly.