Logger32 just auto updated to version 3.50.336 and it would appear the "eMail alerts" may now be working properly. I see the set up screen for email-sending has changed since the last software version. I didn't change any of my settings (I'm using a Gmail account), but it would appear that my problem has been resolved. Perhaps more was changed than just the set up screen?
I've received about 10 spot-notifications since upgrading to version 336 and so far there have been no failures. I'm hopeful and optimistic.