Are the emails being sent from Marketo really hitting the inboxes? Part – 2

by Aakansha Tyagi on July 12, 2017 , Comments Off

What should be done to handle the situation described in Part 1?

As mentioned in Are the emails being sent from Marketo really hitting the inboxes? Part 1, Marketo marks a record Email Invalid only in case of an incorrect email address. So it is important to devise a process that can potentially help marketers identify hard bounces and mark them Email Invalid. This way Marketo will not send those leads any email in future.

Here is a list of standard checkpoints that will help to improve the email delivery:

  1. The Response Code needs to be reviewed to examine the issue.
  2. In case the IP is blacklisted, contact must be made with Marketo Support.
  3. SPF/DKIM needs to be properly set up.
  4. Email content should not have any obvious spam words or large images that can increase the spam score.
  5. If the spam trap is identified, it should be removed.
  6. The list of email addresses should be examined to get rid of obvious typos like an extra space or misspelled email domain.

Marketo provides an option to filter out the email bounces based on the numeric categories. A few smart lists can be created for different bounce categories and also Email Suspended Cause can be reviewed. Based on these Email Suspended Cause marketers can determine which records need to be marked Email Invalid and which need not.

On further analysis and research, a few more response codes are identified that will help mark the hard bounce leads as Email Invalid. Below are some of those keywords:

1. access denied 16. no unauthenticated relaying 31. rejecting
2. bad email 17. non-existent 32. requires server authentication
3. blacklisted 18. not allowed 33. source blocked
4. blocked 19. not authenticated 34. unable to verify destination address
5. connection refused 20. not available 35. unauthenticated mail
6. email bad 21. permanent failure 36. unavailable
7. error 22. prohibited 37. unknown address
8. invalid 23. recipient address rejected 38. unknown recipient
9. invalid address 24. recipient invalid 39. unknown user
10. invalid recipient 25. recipient not 40. user address
11. invalid user 26. recipient rejected 41. user invalid
12. mailbox unavailable 27. recipient unknown 42. user not
13. message refused 28. refused 43. user unknown
14. no longer 29. reject 44. verification failed
15. no such 30. rejected 45. virus

Here are some suggestions on how a process can be created to mark the hard bounce records as email invalid for automatic suppression:

  1. Create a central smart campaign
    • This will look for the response code. If the response code has any of the above keywords, it will mark that record as Email Invalid.
  2. Maintain a hard bounce count field
    • This should be initialized to Zero (0) for a New Lead.  A central smart campaign will be triggered every time a hard bounce happens, and will increase the count of this field by one. In Marketo the mathematical calculation cannot be done in Marketo on the integer type field.  A score type field in Marketo needs to be created for this purpose. It can be named Bounce Score.
  3. Create another smart campaign
    • This will trigger on the lead that reaches a Bounce Score of more than 2. At this point, the contact will be added to a central list – System Hard Bounces List. There can be instances where email is sent again and again to bounce records, which may cause a reputation issue, even if it is a soft bounce. So, it is best to mark the record as Email Invalid if the ‘Bounce Score’ reaches to 3.
    • The other suggestion here would be to create a smart campaign that increases the Bounce Score and executes the lead only once a day. Even if the record was bounced multiple times in one day, the Bounce Score will increase by one only. This is recommended because it may happen that the bounce is resulting from blacklisting or some technical issue at the receiver end that might take up to 24 hours to resolve.
    • In addition, SystemHardBouncesList can be subscribed to the concerned person from Marketo who can do manual review of the response code. Also further on that basis one can reset the Invalid Email if required.
  4. Define another smart campaign on Email address update
    • When a contact’s email address is updated, the campaign will check if the Bounce Score is > 0. If yes, it would make the Bounce Score zero (0), and remove this contact from the central SystemHardBouncesList so it can be further used in bulk emails.
  5. Move to a dedicated IP
    • IP addresses and domain names play a major role in email delivery.
  6. Create smart list – BulkEmailSuppression
    • This smart list criterion will be setting all suppressions in one place, i.e., all members of SystemHardBouncesList, all competitors, test records, Invalid emails, unsubscribes, etc. This central smart list should be used as a final suppression in every Bulk email campaign (instead of defining various suppressions in each campaign). For transactional emails, a different suppression list should be used, and usually hard bounces should not be used as a suppression on transactional emails.

Finally, keep enhancing the smart campaign (setup in #1 above) to automatically mark bounce records Email Invalid.

The above will certainly help marketers drive the email delivery rates for their marketing emails.

Thank you for taking out time to read this. Please share your feedback and comments.

RightWave is delighted to provide its customers with more details on the features, drawbacks, and implementation steps, and can assist in the process. For more information on RightWave’s services, please Contact Us.


1.  Edward Masson, Making sense of Marketo email bounce categories, Champion Program, Jul 14, 2015

2.  Josh Hill, Marketing Rockstar’s Guide to Marketo, 2012

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