Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/MicroDexed/src/commit/e37d82acfe2ae2f778bb6c04d8995d3d800ac997/third-party/TeensyVariablePlayback/extras/soundio/sd_play_all You should set ROOT_URL correctly, otherwise the web may not work correctly.