Xbox One doesn't allow me to change my gamertag?

I've followed the instructions provided here to change my gamertag:

How to Change Your Xbox Gamertag

Unfortunately, when I get to the area where I can "Make my own", and I enter the desired gamertag, I am simply brought back to the previous screen, where I can either select a premade gamertag, or have the option to make my own again.

Does this mean that the gamertag I want is taken?I sincerely hope not. If not, what do I do?

Sorry if this is posted in the wrong area! Thanks!

:)

 

I can not change my Xbox back to my home xbox.

As of right now I cannot change my Xbox at my current home to my home xbox and thus this doesn't allow for me to play any offline games.

 

Evolution DMS2004UHD/Wave Broadband

Xbox One won't work with the "guide me", will let me choose the right set top box, but it doesn't actually allow you to change channels. Anyone have any luck with this?

 

There two plossable reason. It has been blacked listed because it gose agienst tos or it was taken.