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.