Why has Apple ID has been disabled?

Apple ID is locked or disabled

If you have changed your password, have you followed the steps in this article?

What to do after you change your Apple ID or password - Apple Support I suggest doing this before you change your Apple ID or password.

If necessary, contact iTunes Support. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.

iTunes Support

iTunes Support – world wide

After update to iOS12, my Apple ID keeps getting disabled at least once a week. I always unlock it, set it up again on all of my devices and it happen again in a few day (in last 3 weeks it happened 3 times).

2 days ago, it also happened to my wife...

It is very annoying. We didn't have this problem ever, until update to iOS12...