We are using emails from our membership. Many of these are people that I know personally and email everyday. Two of those came back bounced.
There are a number of reasons that an email could be bouncing. If you’re able to email them directly but are having issues getting through using our email campaigns or send email actions, I would immediately guess that their server setting are blocking our automated emails. Having their team whitelist our IP addresses will likely help out with this. Take a look at this page to get our domains and IP addresses: http://help.surveygizmo.com/help/article/link/whitelisting-ip-addresses-domains
This document also goes over email bounces and may have some useful information for you: http://help.surveygizmo.com/help/article/link/bounces
I hope this helps!