Google, Yahoo, and Microsoft are in the process of switching over to SHA2 SSL certificates. That's the cause of 17-714 codes you're seeing.
As a workaround, you can scan only to G-Mail addresses using the following setup:
aspmx.l.google.com (instead of smtp.gmail.com)
Port 25 (instead of 465 or 587)
Encryption type None, rather than SSL/TLS
It's an extra step to receive the scan into a G-Mail inbox and then forward it on, but it's a workaround until a point a SPAR is or is not developed.