I'm trying to modify my last name in my Outlook.com account, and I've tried to sign up with a new outlook account, and they say that my last name is incorrect.

My last name is Cuenca, as a spanish city, but, which is the problem? I cannot understand it! How can that be incorrect? That's my real last name and Outlook.com doesn't let me sign up a new account with it.

I hope someone has a clue.

Thank you all!