Computer is Dell Latitude 3189. When the fault occurred Windows 10 version 1909 was installed and had been when Teams was installed. Teams was working fine for 2 months with camera, then someone comments that they can't see my video. From my end the preview was still working fine so I assumed all was OK. There were no updates or changes made to the computer that I am aware of between it last working OK and others not seeing my video.
I have updated to 20H2, uninstalled Teams and re-installed both an earlier and then the most recent version, uninstalled camera and re-installed, deleted cache in Teams, checked Firewall settings, checked camera settings in teams and windows and probably a bunch of other stuff I can't remember right now to no avail.
The camera works fine in the Teams web version with preview OK and video out OK, but desktop app still has the preview OK but video out not. If I use the Test Echo check then the preview is OK and the full screen out video is briefly live but after a second reverts to the TE logo blank screen.
What next? Could just use the web version but the daftness of this fault is bugging me now.