Problem of Changing Apple ID
I'm using my gmail address as my Apple ID. But, Now I want to change my Apple ID to my iCloud mail address. But, I tried to do so several times.
But, an error is occurred saying that "Your Apple ID can not change at this time, please try again later."
Why is it happened? Please help.
I need to use my iCloud mail as my Apple ID.
Thank You!
iPhone 6s, iOS 11.2.6