Why do I prompt for this error when loading data：
LogCesium: Error: [2023-03-23 17:17:03.332] [error] [TilesetContentManager.cpp:731] An unexpected error occurs when loading tile: Connection failed.
That most likely indicates the URL is invalid, or your network is denying access to it. Perhaps your system requires a proxy, and Unreal is not set up to use it? If you can provide more details, we might have more ideas.