As much as we'd prefer to encourage dialog from everyone, we can't allow Gmail addresses to be used when registering due to Google's draconian spam policies without prior authorization.
The problem is spammers create Gmail addresses (or use a fake one), they then use this to sign up here, our server sends an email to verify addresses, and Google then treats the verification message as spam. Google then downgrades Packetizer's email reputation, thus preventing us from sending normal email to Gmail users.
Nobody else does this to verification messages, so use any other address when signing up other than Gmail. If you must sign up using a Gmail address, contact support first. We can then add you to a pre-approved list.