Youtube iframe not playing within a certain domain - why?

Question

We are a motorsport media outlet (the biggest in Germany). When embedding videos (any video!) from youtube, for some reason, this doesn’t work anymore.

"debug_error": "{"errorCode":"auth","errorDetail":"0","errorMessage":"Video nicht verfügbar","Ak":"Dieses Video darf nicht auf dieser Domain gezeigt werden","NQ":"0;a6s.0","hB":2}",

The same video embedded on our "sister"-page https://www.formel1.de is working correctly. So, the reason for the error CANNOT be the video itself.

I made some test pages
OK: https://www.formel1.de/ytembedtest.html
OK: https://www.ms-total.com/ytembedtest.html
NOT OK: https://www.motorsport-total.com/ytembedtest.html
(The source is always identical)

Here's a video what's happening when we're trying it:
https://www.youtube.com/watch?v=3DdZfJai3qA

How can we fix it? Who is to contact? Please help Google!

• Benjamin Loison: On my side the embed video jh9raOS884g on the link your shared works. Am I missing something ?
• PapuaQ: So when you press "play" the video starts? That would be surprising. For me, the error occurs - and for all colleagues it's the same
• Benjamin Loison: I recorded this video to show you how I see, correctly IMO, both links I sent using a Firefox private window from a Switzerland IP.
• PapuaQ: I'm baffled, @BenjaminLoison :) Even if I try it with swiss VPN - no change. Could you please check the links in the edited version of the question? I provided three links to test embeds and a video of what we see when trying it
• PapuaQ: @BenjaminLoison Ooooh, thank you. It doesn't remove the ban - but the old way of embed through embed is working again with a header to prevent referrers to be sent. That is good! Thanks! (I guess you're browser didn't send a referrer in this case, that's why you could see the video.) But the fundamental problem stays the same. If motorsport-total.com is a referrer, videos are blocked