See If you can't connect to the App Store, iTunes Store, or other Apple services https://support.apple.com/en-us/HT201400.There have been quite a few Apple server connection problems lately. Among other things, see Check Apple’s System Status page.
And, given the recent connection problems, I suggest you use my search link in trying to solve your problem verification required app store. You will see a number of links that are related to your problem. I have not seen a definitive solution for it though.
If you want to contact Apple Support to deal with your problem, see:
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 one.