Thanks, Moderator, for the quick reply.
(I had already found the link you posted.)
But now I am embarassed to say that the problem was on my end.
Somehow Windows 8.1 had changed its time zone settings without telling me. My desktop showed the correct time, but my clock was really an hour ahead in a time zone that was an hour behind.
Apparently the incorrect base clock messed up the Verification timer.
Well, maybe we can add this to the previous troubleshooting link.