Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/MicroDexed/src/commit/688c60720a60deca88290199d8911f8162dd1b12/third-party/ArduinoJson/examples/JsonParserExample You should set ROOT_URL correctly, otherwise the web may not work correctly.