I logged back into my iCloud account and everything worked except sending mail from my iCloud account in Apple Mail (I receive iCloud e-mail with no problems). I then logged my MacBook Pro back into iCloud and the problems started. When I got my computer back, I signed out of my iCloud account on the loaner Mac and erased its hard drive, taking it back to its factory settings. While it was gone for service, I used a replacement MacBook Pro that I logged into my iCloud account to keep things synced for me while I worked on the loaner machine. I sent the computer off to have its battery replaced back in June (and Apple also swapped out a problematic butterfly keyboard at the same time). I use Apple Mail with a combination of e-mail accounts, including Gmail, 3rd party e-mail, Microsoft Exchange, and iCloud. I am using a 15-inch 2018 MacBook Pro with 32 GB of RAM and a 1 TB SSD drive running macOS 11.6 (latest version). I've been trying to work with Apple Support on this issue since mid-July and keep getting bounced around in their system and have yet to get any help in resolving it. I'm at my wit's end trying to solve this problem.
