Cesium for unreal building to hololens2 success! but no see anything, why?

Packaging to Hololens2 , At run time, i can’t see anything,
cesium for unreal version is 1.6.5
ue4 vesion is 4.7


Can you confirm that there is a light in your scene? If you are using CesiumSunSky, try removing it and replacing it with a simple directional light.