Nickname change

Hello guys,

I bought a Nickname change, but i can not change my name. Always comes this error, when I want to confirm my new Nickname:
Nickname contains improper words

The new Nickname should be one of this:
-gEW?
-dEW?

Is it, because I have a questionmark in my name? If yes, I don not understand, why i can not have a questionmark, because a friend of mine have this name:
-pEW?

Attached a picture from the error.

Thank you. Attachment not found.