Troubleshooting Deliverability Issues - Bounced Messages

If you are maintaining a good sender reputation, following best list practices and using a dedicated sending IP, then you are less likely to experience major deliverability issues. However, there are times you come across some bounces and blocks, so ruling out major pitfalls may help get to a solution. With that said, it is important to remember that mail receivers and spam filters are protecting their users from spam and do not fully disclose their filtering rules (each system has a different set of rules), so sometimes it can be difficult to get to a specific resolution. To assist you in troubleshooting a deliverability issue, you can follow the steps below to rule out some of the major causes.

Check DKIM authentication on sending domain(s):

  • Navigate to Admin > Setup > Email Authentication and follow the steps here to test.
  • Using this template, create an email address based on an email account you currently own. For example, to send the results to: the sample message should be sent to "" You would then create a mailing in Informz (or use an existing one) and publish the email to your unique address that you created. You will receive the authentication results to your email account (example below of SPF and DKIM passing)

                Summary of Results
               SPF check:          pass
               "iprev" check:      pass
               DKIM check:         pass
               SpamAssassin check: ham (Note: this can be ignored for the authentication tests)

If the DKIM check is neutral or failing, then it is highly recommended DKIM authentication is completed before continuing to the next step.

Check the setup and content of the mailing

  • Make sure the “from” address used for the mailing has been authenticated with DKIM.
  • If there was a large spike or dip in volume, some mail receivers will classify the message as spam.
  • Check to see if there are any exposed URLs in the body of the mailing (ex: If so, cover them with text or an image to avoid being misconstrued as a phishing attempt.
  • Does the mailing contain any third party or short links? (Ex:,, etc) If so, consider using an alternative because short links are typically blacklisted and may cause your emails to to be blocked or classified as spam.
  • Are any URLs used in your mailing on a known blacklist? You can check your URL's reputation here.
  • If using images in the body of your mailing, make sure you have enough text to go along with it in order to create a good balance. Using only images with no text can look suspicious because spammers have been known to hide text and other malicious content embedded in an image.

Look at the sent mailing results

1. Check to see if you received any subscriber complaints or unsubscribers in the Key Metrics tab of the sent mailing (Mailings > View > Sent). This is a key component in determining your sender reputation and how your mail is being classified.

2. Look at unsubscribe reasons which help you to answer some important deliverability questions (do individuals consider your messages "spam", are you sending too frequently, are you sending to the wrong audience, etc).

3. Select one of the bounce types in your mailing (soft, hard, or blocked) in order to get to more detailed info.

4. Select a recipient from the list and navigate to the Mailings tab then select the “Blocked” or "Bounce" link to view the detailed error message.

5. Look for the “Diagnostic-Code" within the blocked or bounce message details. Sometimes you will be able to see what may have caused the bounce to occur (spam content, ISP or spam filter block, poor sender reputation, blacklisting, etc):

6. You can see if a block is affecting specific domains if you navigate to the Details tab > Non Delivered > Domain Blocks.
If the block is concerning a small, private domain, we recommend doing this.

If the block is concerning a major ISP, such as AOL or Comcast, you may want to submit a ticket to request the block be lifted. You can also submit a case for additional deliverability assistance.

To sum things up...