Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/Teensy-reSID/src/commit/395a1372ea8276e23a64d88110a9c4d3e1297063/examples/reSID
You should set ROOT_URL correctly, otherwise the web may not work correctly.
Frank Bösing