Background 3D preview not available

Hi all,
I am trying to use dynamo for revit but I do not see any background 3D preview within Dynamo.
Revit 3D preview is avilable.
I have tried to figure it out without success.
The version is 1.3.4.666, GPU Quadro K2000.

I will be pleased to receive any idea.https://global.discourse-cdn.com/business6/uploads/dynamobim/original/3X/f/6/f68fbd005ea340de766aeb7d62592068be8b6d8e.mp4