Apple ID

Is this your problem, a somewhat "new" known issue that Apple is actively working on? 

Note that some have solved this problem by signing out of iCloud, restarting their device, signing back in.

And, I can't guarantee a solution, but, see:

Update Apple ID settings iphone https://discussions.apple.com/thread/251180098

And see these search results: update apple id settings: https://www.google.com/search?client=safari&rls=en&q=update+apple+id+settings&ie=UTF-8&oe=UTF-8  You will find quite a few reads that are directly related to your problem. You also may want to use the support options below in dealing with your problem.

Get a call from Apple support to help solve your problem using this

link https://getsupport.apple.com/?caller=kbase&PGF=PGF63005&category_id=SC0245&symptom_id=23362

Apple ID Support https://support.apple.com/apple-id

Apple ID account security for country-specific and region-specific help https://support.apple.com/en-us/HT204169

Get Support: We’re here to help https://getsupport.apple.com/. Go through the options to find the best support option.

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

What to do after you change your Apple ID or password - Apple Support.