Can't use my nickname as Xbox gamertag (unsolved)

I understand, Haktes. However, if you're getting the said prompt it means that it's not yet available according to Xbox.

Hi, I hope you're doing great out there. I am an Independent advisor and I am here to help you in regard to your concern.

According to Xbox support:

"If you receive a message that says a Gamertag is unavailable, this means that you’ll need to try another. The Gamertag that you’re trying to create is either inappropriate for the Xbox service or can’t be used at this time."

You may need to try a different one or try some modifications such as adding xXGamertagherexX, this is just my personal suggestion.

For your reference, you can check this link: https://support.xbox.com/en-US/help/account-pro...

This is not helpful, I want to use my nick that I use everywhere and know the reason why it can't be used...

My original gamertag was 10 characters long and the new one with space is 11. So I think it has nothing to do with character limit.

And yes I was given that prompt where I was told my new gamertag will be "nick name" and my old one "nickname" will be available for anyone.

Interestingly I can choose "nickname" on the account where I changed the gamertag to "nick name" (for a price of course) but not on the other one where I intended to use "nickname" gamertag.

same as my gamertag is my nickname