I tried a different network and it may have helped. I tried several things, and it's hard to say what exactly it was (or if it was simply the passage of time if maybe Apple had something going on).
However, today, with another device, I encountered the same thing. In this case, I had turned on they keychain in settings but didn't notice the "activate" option that I had to use. Going back to settings, it showed as pending. After doing the activate. I got the same error, but in this case, it was doing a data sync...I just wish we knew it was actively doing something with a progress of some sort.
Thank you for taking the time to help, Max.