VIVE Pro Eye (with SteamVR) Display issue

[hguo]

I am using a VIVE Pro Eye with SteamVR and SRanipalRuntime, and I am trying to run scripts on Vizard 7 Enterprise.
Anything from Vizard displays nothing (black screen) on my HMD display. I could still see the grid on the edge of my play area, but I can see nothing from Vizard.
I can see the connection is established as the winviz application started running on SteamVR. Also, the window on my monitor was showing the view with position of the HMD tracked. The controllers could be tracked as well. The only problem is with the HMD display.
I tried both examples: viveProEyeExample.py and steamvr.py, and also vizconnect. All of them give me the same thing.
I have no problem running SteamVR home, or other SteamVR game applications.
Tried restarting applications/machine, re-installing Vizard, and SteamVR, did not work.
Please help. Thanks!