Domain verification fails on my account

I try to add a new domain under my Business. I cannot use DNS verification, but only HTML or meta-tag. Even if I implement those correctly, I still get the following error when I click "Verify":

"This content is no longer available The content you requested cannot be displayed right now. It may be temporarily unavailable, the link you clicked on may have expired, or you may not have permission to view this page. Learn More"

I asked a friend to ad my domain for a test under his account, temporarily setting his verification file, and he succeeded on the first try. So this is related to my account, not to my domain.

Any idea what am I doing wrong?

Asked about 2 months ago