Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/MicroDexed/src/commit/6cec3e5756f461529ae17cd0805dc6e5334f1cd5/doc/images/LCD_characters_green/d.png
You should set ROOT_URL correctly, otherwise the web may not work correctly.