I get this error in the Store and in the Mail app when trying to sync my mail.
So i deleted the account from the comp and tried to re-add it. But it keep telling me it can't do that.

I have a Windows Phone and other computers reggistered with that account, no problem.
But on this computer it just wont let me. Any ideas?

I Just upgraded to windows 10 from windows 8.1 where i also get that error suddenly.