Yep same issue.
i have multiple email accounts on my ipad and iphone. All the outlook/hotmail ones are continiously asking for the password.
Unders settings / mail and the account it shows “Re-enter Password” in blue. Entering the password can take a few attempts but onve it is accepted the blue message goes and all is ok on thatacco7nt for a few hours but then it comes back.
hapening on an iph9ne 7 and an ipad since they were upgraded to ios 14.1
14.2 now out so am going to check if that fixes the issue.