Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/scriptform/src/commit/7bd6809fffbcfd5d59d11bf7d04193b310f43f29/examples/static_serve/static/ssh_server.png
You should set ROOT_URL correctly, otherwise the web may not work correctly.
