What are Hard Bounces?

A hard bounce indicates a permanent reason an email cannot be delivered. Here are some common reasons an email may hard bounce: 

  • Recipient email address does not exist (including misspelled addresses)
  • Recipient email server has completely blocked delivery
  • Domain name does not exist
  • Mail server (or MX records) misconfigured at the domain
  • Mailbox has reached storage quota/limit and can no longer receive new emails
  • Dormant/inactive email account was used to signup
  • Mailbox or mail server settings/filter that may automatically reject inbound emails from unknown recipients

Having a high volume of email addresses on your list which are hard bounces can be dangerous to your deliverability as spam filters can view these as a red flag.

How Prefinery handles hard bounces

When emails are identified as a Hard Bounce or Spam Complaint they are automatically added to your Email Suppression List, which you can view by clicking on Email and then Suppressions in your account. Emails sent to addresses on the suppressions list will be disregarded. 

If you check the profile of the user which your email bounced for by clicking on them from the suppression list, you can see the exact bounce error description and details by going to their Emails tab, then clicking "view details" on the bounced email like as shown below. 

How to reactivate an email address that previously hard bounced

In some cases, an email might hard bounce but still be valid due to the way the server rejected the message. Or, a user may contact you and say that they have fixed a misconfiguration with their email server and that they would like to receive your emails again. 

If you feel an email was bounced incorrectly, you can activate the email again by following these steps:


Click on the Email link in the left-hand sidebar and then on Suppressions.


Find the email address of the user you would like to reactivate.


Click the Reactivate button next to the email address. 

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