Gmail will retry for... [STOP ACTION]

How do I stop Xenforo from retying to send emails?

More Info

I sent a mass email from XF 2.xx through a Google Apps account. Mail Delivery Subsystem is bouncing several errors back: address not found, delivery incomplete, message blocked, and message not delivered. Many emails sent successfully.

Server error log:

ErrorException: Email to emailname@emaildomain failed: [E_WARNING] fwrite(): SSL: Broken pipe...

Gmail will retry for... [STOP ACTION]

source https://xfmaster.com/threads/gmail-will-retry-for-stop-action.16034/