Hard Bounce Failures

Hard bounce failures indicate email addresses are permanently undeliverable.

Possible causes

Hard bounces occur for multiple reasons, such as address errors, bad domain names, unknown users, and closed accounts. Examine the specific failure types to determine the likely causes.

Suggested actions

Invalidate the records immediately and remove them from your list. Contact the recipient for replacement or corrected email address.

Note: We automatically place all email addresses which hard fail on the blacklist so they are suppressed from future mailings.

The email address is valid for the domain but nonexistent. Generally, this means the account has been closed for some time.

Possible cause: Stale data

Your list may contain a high number of undeliverable addresses if you haven't recently used it or if too much time's elapsed since you obtained the addresses. This is an important data point to review since it's one of the main reasons mailbox providers block email messages.

Suggested actions

  • While you should adjust the frequency of your messages according to your recipients' preferences, you should also review all segments of your list on a regular basis to ensure brand visibility, continuity of communication, and address deliverability.

  • Set standards for the first communication after you obtain an email address (5 to 10 days). This reduces the liklihood the recipient will complain later.

  • If you mail to an "old" segment, do a test before full you send to the full list. Send the mailing to a subsets of the group to avoid spikes in Unknown User failures.

Possible cause: Poor data capture

You may not adequately validate email addresses when you obtain them.

Suggested actions

  • Send a follow up email to new recipients to confirm opt-in permission and validate the deliverability of the address they provided. If it bounces for reasons that indicate the address is invalid or inactive, remove the email and contact the recipient for a new or corrected address.

  • Require double entry of email addresses to minimize typographical errors.

  • Perform address hygiene to correct common misspellings on major domains before you add large quantities of new records to your list. After you correct addresses, send confirmation emails to verify the changes are accurate.

Possible cause: Unreliable data source

When you purchase email lists, you risk introducing undeliverable records to your list.

Suggested actions

  • Know your data sources. Investigate their data compilation and management practices and confirm consent and deliverability before incorporating their addresses into your list.

  • Perform address hygiene to correct common misspellings on major domains before you add large quantities of new records to your list.  After you correct addresses, send confirmation emails to verify the changes are accurate.

  • Contact the recipient for a replacement email address.

The email address has a domain name that is invalid or no longer exists.

Possible cause: Stale data

Your list may contain a high number of undeliverable records if you haven't recently used it or if too much time's elapsed since you obtained the addresses. This is an important data point to review since it's one of the main reasons mailbox providers block email messages.

Suggested actions

  • While you should adjust the frequency of your messages according to your recipients' preferences, you should also review all segments of your list on a regular basis to ensure brand visibility, continuity of communication, and address deliverability.

  • If you mail to an "old" segment, do a test before full you send to the full list. Send the mailing to a subsets of the group to avoid spikes in Unknown User failures.

Possible cause: Poor data capture

You may not adequately validate email addresses when you obtain them.

Suggested actions

  • Send a follow up email to new recipients to confirm opt-in permission and validate the deliverability of the address they provided. If it bounces for reasons that indicate the address is invalid or inactive, remove the email and contact the recipient for a new or corrected address.

  • Require double entry of email addresses to minimize typographical errors.

  • Perform address hygiene to correct common misspellings on major domains before you add large quantities of new records to your list. After you correct addresses, send confirmation emails to verify the changes are accurate.

Possible cause: Unreliable data source

When you purchase email lists, you risk introducing undeliverable records to your list.

Suggested actions

  • Know your data sources. Investigate their data compilation and management practices and confirm consent and deliverability before incorporating their addresses into your list.

  • Perform address hygiene to correct common misspellings on major domains before you add large quantities of new records to your list.  After you correct addresses, send confirmation emails to verify the changes are accurate.

  • Contact the recipient for a replacement email address.

The email address has a format or syntax error (multiple or missing @ sign).

Possible cause: Poor data capture

You may not adequately validate email addresses when you obtain them.

Suggested actions

  • Send a follow up email to new recipients to confirm opt-in permission and validate the deliverability of the address they provided. If it bounces for reasons that indicate the address is invalid or inactive, remove the email and contact the recipient for a new or corrected address.

  • Require double entry of email addresses to minimize typographical errors.

  • Perform address hygiene to correct common misspellings on major domains before you add large quantities of new records to your list. After you correct addresses, send confirmation emails to verify the changes are accurate.

Possible cause: Unreliable data source

When you purchase email lists, you risk introducing undeliverable records to your list.

Suggested actions

  • Know your data sources. Investigate their data compilation and management practices and confirm consent and deliverability before incorporating their addresses into your list.

  • Perform address hygiene to correct common misspellings on major domains before you add large quantities of new records to your list.  After you correct addresses, send confirmation emails to verify the changes are accurate.

  • Contact the recipient for a replacement email address.

The email address is valid for the domain, but is now closed or suspended.

Possible cause: Email address change

At 33% address churn per year, closed accounts is a major cause of list attrition.

Suggested actions

  • Given the rate of address churn, you should continually maintain proper list hygiene and mailing practices. Consider email a relationship with the recipient and nurture it appropriately.

  • Request second/back-up E-mail address or new/better one as standard part of your data capture and ongoing communications.

  • Contact the recipient for replacement E-mail address if now closed.

Possible cause: Stale data

Your list may contain a high number of undeliverable records if you haven't recently used it or if too much time's elapsed since you obtained the addresses. This is an important data point to review since it's one of the main reasons mailbox providers block email messages.

Suggested actions

  • While you should adjust the frequency of your messages according to your recipients' preferences, you should also review all segments of your list on a regular basis to ensure brand visibility, continuity of communication, and address deliverability.

  • If you mail to an "old" segment, do a test before full you send to the full list. Send the mailing to a subsets of the group to avoid spikes in Unknown User failures.