Can`t attach account

hi there guys. when i tried to link the account it give me error 400 (region is europe)

Im having the same problem as you. The difference is that i’m playing on the US region.

Had the same Problem and I know of a friend who has the same Problem.
After she asked me for help I tried to change the language to German, which failed. Tried to login from the German version, which failed.
Then I made a second account, got the mail and followed the linktherein and then tried to link my battlenet (EU) which led to aforementioned error 400.
Login to my original Account vie the english front worked without problems. My battlenet Account and my Character, as well as my Guild is properly (well, almost) linked.
Almost properly, as I’m an Officer, however, I have no rights to change anything here on the Page.