Understanding bounced emails in Klaviyo

You will learn

Learn about the reasons that emails can bounce, as well as how to view and suppress bounces in Klaviyo.

A "bounce" occurs when an email is either not successfully delivered or is rejected by the recipient's email provider. If your account has a high number of bounces, this can have a negative impact on your deliverability rate.

There are two types of bounces:

• A hard bounce occurs when an email cannot be delivered due to a permanent reason. This could be caused by a variety of reasons, including a misspelled email. Klaviyo automatically suppresses any email address that hard bounces.
• A soft bounce is always caused by a temporary reason, such as when a recipient's inbox is full or when their email server is momentarily down. If an email soft bounces more than 7 consecutive times, Klaviyo will suppress this address.

Why emails bounce

There are several possible reasons why an email address may hard or soft bounce:

• Email address doesn’t exist
  The contact could have provided a false address or made a typo in the address. If you are unsure, you can try correcting the email address and sending a one-off email. If the email still bounces, this address should remain suppressed.
• Email is undeliverable
  The email was unable to be delivered due to an error with the server, etc. 
• Mailbox is full
  If the profile has opened emails from you in the past, they may need to empty their mailbox.
• Vacation/Auto-reply
  The contact may have set a temporary auto-reply. If there is previous activity in the account, they may need to turn off auto-reply.
• Blocked Email
  The receiving server has blocked the incoming email.

Viewing hard bounce and soft bounce metrics 

To see overall bounces across all campaigns, view the Campaign Trends Report. Additionally, you can use segments to identify addresses that have hard or soft bounced.

If you want to see what type of bounce a customer experienced, click into the customer profile and search for the bounced email event. You can click on the timestamp for the event on the right-hand side and see whether the bounce recorded is hard or soft.

Removing bounced emails

Klaviyo will automatically suppress emails that hard bounce, and then exclude them from future emails. You can see these email addresses by clicking the Profiles tab and selecting Suppressed Profiles in the upper right-hand corner of your account.

Then, choose all email and email bounce from the dropdowns.

If an email soft bounces more than 7 consecutive times, Klaviyo will suppress this address.

Suspicious emails in Klaviyo 

When an email hard bounces at least once across the Klaviyo infrastructure, it is marked as suspicious. This means that even if they have never hard bounced in your account, they have previously hard bounced in another Klaviyo user's account.

 Suspicious emails are automatically skipped from receiving emails. This is done in an effort to preserve your sending reputation, as well as the sending reputation of other Klaviyo customers since sending to invalid addresses can negatively impact both IP and domain reputation.

 If you believe that a profile or profiles have been marked suspicious in error, please reach out to our Support Team, and provide us with evidence of the email address still being valid. Typically a screenshot of an email from the said profile would be sufficient.

 Please make sure that this screenshot clearly shows the following:

• The email address that has been marked suspicious.
• The timestamp of the email address being delivered an email on a date after the profile was marked suspicious in Klaviyo.

Additional resources

• List cleaning
• Understanding email deliverability
• KPI decrease troubleshooting