Whether you’re running cold outreach, nurturing leads, or sending newsletters, your campaign’s success hinges on one foundational assumption: your emails are getting delivered.

But what if they aren’t?

An email bounce occurs when your message can’t be delivered and is returned by the receiving mail server. It might sound like a small hiccup, but repeated bounces can get your domain flagged or blacklisted — crippling your deliverability and trust score.

So, what is email bounce in detail?

• Hard Bounce: A permanent failure. Examples include sending to a non-existent or mistyped address like [email protected]. These addresses should be removed immediately.


• Soft Bounce: A temporary failure, like an inbox that’s full or a server that’s down. These can be retried but monitored.

Here’s why it matters:

• Too many bounces damage your sender reputation.


• Internet Service Providers (ISPs) may start flagging your domain as spam.


• Your email platform might suspend your account due to poor list hygiene.

To avoid these issues:

• Regularly verify your list with a cleaning tool.


• Authenticate your domain (SPF, DKIM, DMARC).


• Don’t buy email lists. Use opt-in strategies instead.


• Monitor and manage bounce reports in your ESP dashboard.

If you’re curious to explore more technical and tactical solutions, this well-explained resource on what is email bounce is a solid place to start.