I am completely new to using Marketing Cloud so this may be a stupid question. I scheduled 2 emails to go out to separate audiences. The lists were deduplicated. I imported IDs and Email addresses into my Data Extension - all IDs had an email address.

I added exclusions for the normal reasons (hard bounces/opt outs etc) .

Each send was set for about 80000 recipients.

Both lists received about 5000 fewer sends than expected. What should I be looking for to find out why they did not send?

1 Answer 1


updated version 09-2021 This comes up so often that I have been updating a continuous "work in progress" document which lists all scenarios that are known to me for step by step debugging.

I've shared the latest version below.

The order of operations might not be 100% accurate, as this is impossible for me to check from the outside (and often doesn't really matter), but for a commercial sendout, here is pretty much what you can expect. For completeness - Transactional just handles "unsubscribed" like "active".

Some things are super common (list detective!!), some are absolute edge cases (like multiple email fields in the DE). But all have happened before!

updated 09-2021, initial version here: https://i.stack.imgur.com/JeLiP.png

  • Nice pic, may I know the source of truth for such content?
    – mario ruiz
    Jan 25, 2021 at 18:09
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    Option a) I guess you have to trust me, I made the chart. Option b) try it out. That's how I came to draw it. Like I say, there is no guarantee on the order of things, but feel free to try them one by one or search stackexchange / the documentation for every single one element. Most of them are pretty easy tests, and no secrets either (an auto suppression suppresses, list detective exists...) . The first post already listed a couple things which are all included, so let's assume it's not completely off. The latest edition was the "double email" thing, feel free to reproduce that. Jan 25, 2021 at 18:16
  • And like I say: It's my work in progress, has been for years. Feel free to add to it in case there are omissions. Jan 25, 2021 at 18:21
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    Oh man, I didn't understand first time that this is house made! :) Excellent, thanks for the note. I was looking for a link somewhere, but after this clarification, you bet man!
    – mario ruiz
    Jan 25, 2021 at 18:27
  • @JonasLamberty it seems I'm having a send complete to 0 sends, due to the list detective step in your diagram. The odd thing is that my list appears to contain both valid and invalid email addresses, but they all fail. Shouldn't the valid emails still go through? Sep 11, 2023 at 17:58

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