Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/MicroDexed/src/commit/55419d4fe9a4ce8aa0f8f5a544d22c5702858a24/doc/images/MicroDexed_Panel/Transparent%20images/Horizontal%20Arrows/Horizontal%20arrow%20Black%20left.png
You should set ROOT_URL correctly, otherwise the web may not work correctly.