Why do emails bounce?

Deliverability Podcasts

So often we view emails as a one-way conversation. In reality, there are plenty of complicated mechanics that go on behind-the-scenes between both sender and the receiving server. But what really goes on when an email bounces? Is it the fault of the ESP? Should we clean our lists of every email address that bounces?

Like everything with deliverability, finding the why behind your email bounce rarely leads to a simple and clear-cut resolution.

In this episode, Alyssa and Melissa explain the technical blueprint of a bounce, common reasons for the dreaded deferral, and a few best practices for stopping bounces before they begin.

how to avoid bounces



(16:10) “Anytime you’re collecting subscribers, ask yourself: ‘Are these people here because they want to receive my emails?’ If the answer is no, don’t send them emails.” ~ @alyssa_dulin

Main Takeaways

  • [09:52] When it comes to bounces, there are hard bounces and soft bounces. Hard bounces are a bit more permanent. If you see a high number of bounces all at once, that’s a sign that something deeper is going on with your email deliverability.
  • [11:53] Don’t delete your bounced subscribers because that makes it much harder to diagnose the problem.
  • [13:03] When you send to a list that results in high bounces often and you’re not addressing those bounces, it can cause deliverability issues.
  • [14:08] If you have a high bounce rate, look for why people are providing incorrect email addresses. Maybe you have an email collection system that’s frustratingly impossible to exit out of. Or collecting emails with pen and paper, for example, always causes human errors.
  • [23:17] If you add a DMARC record, make sure your email is passing!


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Alyssa Dulin

Alyssa is a Deliverability Lead located in Nashville, TN. She loves helping senders reach the inbox of their subscribers. Outside of work, Alyssa enjoys traveling, indoor cycling, and spending time with family.

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