Tks Pankaj for looking into it.
Unfortunately, I doubt very much this particular issue is related to the privacy of the video. We have over a thousand videos on Vimeo and they are all set as "Private", i.e. can be viewed by people with the link.
Well over 200 of those videos are part of difference courses on GuruPro, all setup exactly the same way as the ones mentioned above in this ticket.
I tried the embed approach, and videos work perfectly well without changing any vimeo settings, so I can't see how it could be related to privacy.
Anything else it could be?
This issue started only about a week ago.
Tks,
Serge