Kindleowner_DK,
There's another discussion on this topic here:
https://www.mobileread.com/forums/showthread.php?t=58329
According to some of the posts, there's been a software glitch at Amazon that has since been corrected. A couple of people have said they can now buy books again, without the geographical restriction message. (But others have said they can't.)
Might just be worth your giving it another try.