Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/MicroDexed/commits/commit/dd2df37510c96777df3cb62b67494391aae60bb9/doc/images/LCD_characters_green/U.png
You should set ROOT_URL correctly, otherwise the web may not work correctly.