I ran into this situation recently with an embedded YouTube video in the OER shared with us recently on OEG Live by @JudithSebesta
I spotted in one chapter the clip for The Road showed up as Unavailable.
I shared with Judith, who was perplexed because she could see it fine.
Then my hunch kicked in… I live in Canada, and often I find YouTube clips won’t play here (usually ones for songs or TV shows). And sure enough, I flipped my connection via a VPN tool to use a US based IP address, and I could see the video.
So the vldeo’s author had placed geographic restrictions on it. That’s not very global!
Judith has since changed the clip for one without restrictions, but I was curious how an OER author would know a clip they can see fine will not show up for someone in another country. Thus I found the WatanNetwork tool linked above.
You can see it in action with the URL for the original clip that I could not view in Canada-- https://watannetwork.com/tools/blocked/#url=WEP25kPtQCQ
Thus it shows that the movie is only available in 4 countries: Somaliland, Kosovo, N. Cyprus, and the United States (curious choices there!)
This ought to be useful for making sure any YouTube videos used in your work are globally available.