We are trying to troubleshoot problems .. but none of the symptoms seem to be the same each time. Very frustrating and hard to fix.

The majority of the time, everything works as designed .. the "Thank You" page appears, the "Email Confirmation" is received by the rider and Nancy is able to get the pre-entry.
Other times, the confirmation is not sent, but the entry gets submitted properly.
We are not sure, but think the problems are the fault of our server. They may have had a glitch, due to overloads or updates that we are not aware of. Our server's Spam filters are rather aggressive and may be the culprit. We really don't know.
Until the problems are solved, follow Paul's suggestions above, even if you receive a confirmation. Also, bring a copy of your confirmation with you to Registration.
We apologize for any inconveniences .. and appreciate your patience.