The sender and reply-to details can be customized for each broadcast or sequence email created in your account. These details appear in the “envelope” for your message in a recipient’s inbox so they can see who a message came from.

Take Note
  • The send-from and reply-to email addresses must be custom domain addresses on the same domain. Free email addresses are not allowed here.
  • Custom domain addresses must be authenticated to ensure deliverability and keep your messages out of the spam folder. If you use KartraMail as your sending gateway, you can start the authentication process in your Kartra account.

Sending domains that have not been authenticated will prompt a warning message when you configure an email message in your account.

Email gateway DKIM warning

Example of an unauthenticated custom domain warning

Authenticate Your Domains:

  1. Go to KartraMail DKIM in your account to add your sending domains and start the authentication process.
  2. Follow the Sender Authentication Checklist to complete each of the steps needed to secure and authenticate your domain. The process will take approximately 24 hours to set up, propagate, and test.


You can check the “Okay, I understand that my emails will have low deliverability” box to dismiss the DKIM warning and add your custom sender domain without authenticating your domain.

Doing this will significantly impact the delivery rates for your emails and may hurt your sender reputation. Bypassing authentication is not recommended.