In June of 2016, Gmail updated their DMARC policy.
For many ConvertKit senders, the change had little or no impact on their regular sending. For others, it required a little effort to avoid serious interruption. Either way, it’s worth understanding exactly what changes were made and how it affects you now.
What is DMARC?
It stands for Domain-based Messaging Authorization Reporting and Conformance Policy. It means that emails coming from an @gmail.com account can only be sent from their original servers.
Since you're using our ConvertKit servers to send your emails (and this is true for any other ESP too), your emails sent from an @gmail.com address - using an @gmail.com in the from address - will likely be bounced (read: your Subscribers won't get your emails). Yahoo has had this same policy in effect for some time to cut down on SPAM, but Gmail put the same policy into place to protect it's system too.
What do I do about it?
You’ll want to create an email account using your domain name (ie: firstname.lastname@example.org) and use this for your ConvertKit From email address instead of a Gmail account. You can get an email address for your domain name using G Suite, or through your domain host.
Once you’ve secured your new email address, log into your ConvertKit Account page, (found by clicking on Account in the menu bar), and head to the Email section to update your primary email, and ensure your emails won't be bounced by Google!
NOTE: In ConvertKit, the default email address won't update retroactively for Sequences. You'll need to update existing Sequences to use the new email address rather than your old one.