Postmaster problem with unknown address in our DB

  • 21 December 2020
  • 8 replies

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We have recently imported our DB from SendinBlue to Klavyio.

While sending our first newsletter, we got around 30 postmaster emails to notice undelivered emails + 400 hard bounce. That is alot, we didn’t have that before in SendinBlue.

I went into our DB to remove these, but the strange thing is that these 30 emails address (which generated postmaster) are UNKNOWN and IMPOSSIBLE to find in our DB.

I therefore DONT UNDERSTAND how this is possible?

Can somebody help me?


Best answer by cassy.lee 28 December 2020, 18:26

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8 replies

Userlevel 7
Badge +58

@JNJOYBE How did you import the emails?  Was it via a CSV import?  Sometimes there are characters (or symbols) in some names that get improperly encoded.  Usually these are symbols specific to some names with accents, umlauts, tildes, or non-english characters. Make sure you save/export/open in UTF-8 encoding if your language is primarily “english characters” and UTF-16 if Asian languages.    

Once it’s improperly encoded, they get changed so you won’t be able to find an “exact match” in your original source.  However, they should have some similarities if you try to do a search around it each email.    

Also, check if Klaviyo is integrated with any other email sources or emails coming from your shopping platform - it may have pulled in emails from your ecommerce provider as well.

Finally, ask your developers or partners to see if they recognize those emails.  Sometimes we use test emails or non-existent emails during the testing or integration stage and those emails should have been removed or suppressed (or excluded) from live campaigns!

Hope this was helpful.

Badge +2

Hello Joseph,

thanks for taking your time helping me. We imported via CSV with proper langage. On top, these « ghost » emails are not with special character. See pictures below.

our Klavyio is linked with our Shopify but I double checked, none of these address are from Shopify. 
they are completely unknown and impossible to find in our Klaviyo DB ! But every time we are sending an email, we get these postmaster emails(see below example) :(


Userlevel 6
Badge +9

I think the solutions that @retention suggested are definitely good ones to look at (ie. did a partner/developer create the emails or send and then delete the profile), but this is definitely a bit of a tricky one. As you stated, these emails are also not in Klaviyo, so it’s possible that someone deleted them. We haven’t seen examples where customers are reporting random emails triggering a postmaster. If this is still causing an issue for you, and you’ve verified that not of your partners or developers have created email tests, I can certainly help pass this along to my team to investigate further. Just let me know in this thread or in a DM! 

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Hello again,


we are very new on KLAVYIO. And all people having access to our DB are also looking like me « where does that come from » ?

nobody knows. It’s like ghost.

help is highly appreciated.

Userlevel 6
Badge +9


Thanks for letting us know! I followed up with you in a Private Message with more details about next steps, and I’ll circle back in this thread if we are able to identify the root cause of these “ghost” emails. 

Userlevel 6
Badge +9

Just wanted to follow up on this thread in case anyone else finds a similar problem. We’ve identified the root cause as an automatic forward from a recipient to another email address. Klaviyo only records the original delivery, and not the subsequent bounces since that second profile isn't even in our system. These bounces would not affect your deliverability.


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2.5 years later, we are back with the same problem

email (in our DB) sent to get a postmaster back from which is not in our DB

how to get rid of this?

At the same time, we feel that the performance of our newsletter are abdnormally bad and think there is a link between this problem and the performance

Userlevel 7
Badge +60


Just as @cassy.lee had previously stated, this behavior you’re experience is caused by a recipient/subscriber you’re sending emails to forwarding your emails to other addresses. 

If you wish to prevent this, I would trying to identifying the profile/contact that is forwarding the emails and suppressing them

Since these forwarded emails are not being sent from Klaviyo, but rather sent from an individual’s email, those emails that were forwarded and bounced would not impact your deliverability. However, it would still be a good idea to clean your list on a routine basis to further help prevent these sort of behaviors in the future.