I knew that about 15 minutes into the problem, but it doesn't excuse the fact that I spent about 30 minutes trying to get the review to submit on two devices. My iPad asked me to sign in several times, and at no time did it give me any clue about what was happening. The login messages were sometimes different. Finally it threw an error that said try again later.
So I went to my PC and went through the steps on the website to submit a review for the same app. It was technically "later." There I found roughly the same confusion. No way to know what was happening. First, I submitted it and nothing happened. The dialogue window didn't even close. I hit cancel and went back to my iPad.
Then I came on here and I saw about a dozen other questions about the same issue dating back to 2011! I couldn't figure out if the situation was ever resolved.
And I still don't know whether I successfully submitted my review anywhere.