Why am I not able to use my current iTunes username?

[iMore Question]

Why am I not able to use my current Itunes username. My old username is no longer valid

I used to belong to Comcast.net. I am now using gmail.com. Why can't I use my current gmail email address?

 

[kch50428]

Re: Why am I not able to use my current Itunes username. My old username is no longer valid

http://support.apple.com/en-us/ht5621