Apple ID Disabled

Go to Settings. Do you see any notices about your Apple ID? If not, click on your name and profile picture (above Airplane Mode) and see if there are any notices there about your Apple ID. If there's still nothing there, check your email. Apple has likely notified you about this and has probably sent you instructions on how to reactivate your Apple ID.

Usually, Apple IDs get disabled when someone enters too many incorrect guesses for the Apple ID password. However, perceived location could also be a factor, as my Apple ID got disabled due to me repeatedly signing into iCloud using the Tor Browser (which randomizes your location). I was able to reactivate my Apple ID by going to Settings and clicking on my name and profile picture. As part of the reactivation process, I was forced to change my Apple ID password for security purposes. Afterwards, I was able to use my Apple ID again.

Hope this helps!

Apple ID is locked or disabled

If necessary, contact iTunes Support. Scroll to the bottom of the page in the 2nd link.

iTunes Support

iTunes Support – world wide