Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/music-synthesizer-for-android/src/commit/05355d7ef514aac9e5981c29cc66598be3d78cf6/android/res/drawable-hdpi/eighth_note.png
You should set ROOT_URL correctly, otherwise the web may not work correctly.