I spoke a bit too soon.
After getting a couple of certificates in test mode last night, I tried again today for real and got the same error message. When I went back to test mode, I could not longer get certificates. Looks like a different problem though, ThisPage was generated but with error detail. The ThisPage contents and the debugview detailed log are attached.
I should mention that between the time of the successful test and the next failure, I did a rebuild of the solution after some unrelated template changes.
Thanks.