Get translate in ARKit Face Tracking

I’m using UE 4.27.

I’ve tried the FaceARSample.
When I show the debug mesh.
The mesh always at the center of the screen
while I tilt camera, it does not move to cover on my face.

In my case, I have a StaticMesh
then GetALLArGeometry → cast to ArFaceGeometry → GetLocalToWorldTransform → SetWorldTransform( StaticMesh )
but the StaticMesh always at the center.

How do I solve it ? Let StaticMesh follow and cover on my face ?