Email Deliverability

Help! My email is 100% missing? Where did you put it?!

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One of the most common questions reported by our users is also one of the most maddening to experience as a sender: A campaign is showing as 100% missing. What does this mean? Is this test still processing? Did everyone drop this? More to the point; what value does this even offer? After all, how can you measure your inbox placement if you’re only seeing missing mail?

Fair questions!

First, it’s worth noting mail really can go missing. This result indicates the percentage of mail that didn’t make it to an inbox (check out our Knowledge Base article on missing mail) for one reason or another. However, a result of 100% missing is another story.

Unfortunately, the most common causes for this issue occur on the sending side.

Fortunately, both can be resolved easily. 250ok Support has some tips and tricks to help.


In your day-to-day sending, you may notice addresses get suppressed now and then due to lack of engagement. Many email service providers (ESPs) include this as built-in functionality to ensure your campaigns are performing as well as possible. They have your back. They’re your Star Fleet.

The unfortunate drawback here is that 250ok seed addresses really only engage with your mail when checking links and images. We’re not scrolling, printing, forwarding, etc. in a regular way that will register with your ESP. We don’t have people monitoring these inboxes because we don’t want to skew your numbers. We also have your back.

You probably see where this is going…

Should you consistently see results going missing, it is worth confirming with your ESP that these seed addresses aren’t being suppressed.

Now that we’ve confirmed these addresses aren’t being suppressed, we can dive into the slightly more involved (and definitely lengthier to explain) other potential cause: x-header issues.

X-headers and Extreme

Now and then you may see a reason to test one or more near-duplicates of a campaign in a short timeframe. Maybe you’re testing from different addresses, A/B testing, or adjusting some small pieces of your body copy here and there. Seeing one test show results and another test not show anything can be particularly jarring. After all, how could a few small differences cause something that extreme?

Here’s the good news—they probably couldn’t! It’s moooore than woooords… (Extreme? More than words? Eh?! Eh?!)

We just need something to break these messages apart. It’s possible these results are flowing in; they’re just not making it to where they need to go. Imagine we’re in the reception hall but we can’t find our table. Luckily we just need to take a few steps back to find our seating assignment. We need a unique x-header value for each of our tests.

First, check out Inbox > Settings > and take a look at the number in the Campaign Duration field. 250ok uses the number set here to determine how long we will continue to look for seed test results, but it also gives us a clue. Next, make a note of the values listed next to Campaign Header(s). Let’s take this down.

Now, let’s check to see if an x-header is being included in the send. Within 250ok you can see this by opening an Inbox test and taking a quick look at the Campaign Overview screen. If we are detecting an x-header, we will show it in the same row as the date/time and from address of the test in question.

See nothing? Fear not! Click the Email Preview tab followed by the Header button to view the header for this message.

If an x-header value is being included in your send it will be near the bottom of this header. 250ok is currently able to accept the following x-header types.

  • X-250ok-CID
  • X-rpcampaign
  • X-PVIQ
  • X-Campaign-ID
  • X-CampaignID
  • x-job
  • Tag-id
  • X-10pl8ID
  • X-Campaign
  • X-Campaign_ID
  • x-cid
  • X-eC-messenger-mid
  • X-EMarSys-Identify
  • x-jobid
  • X-Listid
  • X-MailingID

If you don’t see one of these x-header types included in your send, we recommend contacting your ESP for assistance in getting one added into your sends. In the case your provider cannot configure your account to send messages including one of these header types, we offer the ability to embed the X-250ok-CID body tag in the HTML body of your email. Simply include a tag that looks like <!– X-250ok-CID: uniqueid12345678910–> anywhere in the body of your email.

Some best practices for creating a unique value for your header include the following:

  • All X-250ok-CID values should be unique per campaign.
  • Do not include any spaces in the value.
  • Prefix your campaign value with a company name or nickname.
  • Consider including a timestamp in your value. This will help ensure uniqueness.

Now, all of this said, we’re not perfect. While the vast majority of 100% missing mail issues can be explained by one of these two problems, we like to keep in mind that this is technology we’re talking about here, and reminder: We have your back. Don’t hesitate to reach out to 250ok Support for assistance in troubleshooting missing mail issues and stay tuned for more 250ok tips and tricks!