Cesium3DTileset not rendering in packaged build Ue5.3.2 with Cesium 2.2

Those look like a problem with the network. Perhaps the problematic system needs to use a proxy server to access the internet? Unreal Engine unfortunately does not use the default Windows proxy settings by default (are you even on Windows? You haven’t said.)

Some users have been able to get Unreal Engine to use a proxy by setting an environment variable: