Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/MicroDexed/src/commit/907ba61c4b814eae3d650449937745f209fe4f6c/doc/manuals/MicroDexed-User_Manual/images/MicroDexed2.jpg
You should set ROOT_URL correctly, otherwise the web may not work correctly.