HubSpot may automatically stop the sending of your email before it is completed if your email is likely to result in a high percentage of hard bounces. Sending emails to lists with high bounce rates can have lasting negative effects on your email deliverability.
To protect your sending reputation, please complete the following steps before you try to resend your email:
- Confirm that your list is OK to email with HubSpot.
- Make sure that you have imported all of your opt-out lists from other email systems into HubSpot.
- Remove any contacts from this list who haven't heard from you in over 6 months
For more information on email deliverability best practices, check out this article.