Mission Planner 1.3.77 build 1.3.8110.38294 - video link not working

I am unable to get the video link from either OpenHD or RubyFPV working with Mission Planner 1.3.77 running on a Windows 10 laptop.

The video link work ok when I use Windows 10 desktop PC which is running Mission Planner 1.3.75 which demonstrates that the ground station video feed is OK.

I have double checked the firewall rules on the laptop and they are the same as the desktop PC.

Mission Planner video on the laptop did work before I upgraded it to 1.3.77 last year.
and it does work fine in every other respect but just not the video.

I would appreciate any suggestions on what to try next.