Monitoring Email Deliverability: Troubleshooting High Bounce Rates – Part III

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This blog is the third in a multi-part series on monitoring your email deliverability. The first part on managing bounces can be found here. The second part on unengaged users can be found here.

We’ve covered setting up some campaigns and programs to manage bounced or unengaged users on an ongoing basis. Now I want to cover troubleshooting some common email deliverability problems, starting with high bounce rates.

The first thing you should do is figure out if there’s a problem with just one email or if the problem is more widespread. Pull an email performance report and look at bounce activity over the last 30 or 60 days.

  • If you see a hard bounce rate of about 2%, that’s normal.
  • If you see a hard bounce rate of 5-10% on one particular email, but there’s not a problem across all emails, then you do not need to be overly concerned, but you might want to do a little more investigation on the list for that one email.
  • If you see a hard bounce rate of more than 10% or you see 5-10% hard bounce rates on many emails, then you should certainly do some investigation.

How do you investigate? Build a smart list to look for the email addresses that bounced, with a filter down to either the specific email send or for emails sent within a certain date of activity. When you build your smart list, you can add a constraint to the bounced filter for each specific bounce category so you can identify the number of leads impacted by each. For example:


Use the results from the smart list to populate a table like this:

Bounce Type

Bounce Category

Bounce Category Name

Bounce Count

Bounce Percent






Invalid Email Address










Based on the category of the bounce, this will impact the action you take to resolve it. Here are some of the things to think about:

  • How old is the list?
  • Where were the records acquired from?
  • Have the leads opted-in?

Some of the actions that clients commonly take to address bounced emails include:

  • Reconfirming old leads by sending a communication asking them to opt back in.
  • Using a list validation service to test email addresses.
  • Setting up a welcome communication to new leads that come in from less trusted sources to help clean out the emails.
  • Removing forms from in front of assets that generate a lot of bad email addresses.
  • Adding validation to forms to check email syntax.

If you have other suggestions, please share them in the comments!