What Is an Email Bounce and How Can I Prevent It?

What is an email bounce?

When an email bounces, it’s the equivalent of a letter (remember those?) being returned.

This article explains what an email bounce is and what causes emails to bounce. It also explains how bounces can affect the deliverability of your emails.

What is an email bounce?

An email bounce is a message that is returned to tell you the email could not be delivered.

There are two main reasons that an email can bounce.

  • The recipient’s email address does not exist
  • The recipient’s inbox is temporarily unavailable

When you send an email, the recipient’s email provider, such as Gmail, will first checks that the email address exists. If it does, the provider next determines if it’s able to accept emails. If the address does not exist or the inbox is not able to accept emails, a message is sent back to the sender’s provider indicating that the email has been rejected and the reason. In ActiveCampaign, this is recorded against the contact’s record.

Why do emails bounce?

These are a few reasons why emails bounce. Some are a temporary inconvenience while others are symptoms of a problem that must be fixed.

In this section, I talk about some of the reasons an email can bounce.

The email address does not exist (Hard Bounce)

For these emails, the service, such as @outlook.com, exists but the user doesn’t. It’s normal to have a small number of contacts with an email address that doesn’t exist. The address may never have existed, or the account could have been closed.

Temporary bounce (Soft Bounce)

There are different reasons a soft bounce can happen. The recipient’s inbox may be full or there may be a temporary problem with recipient’s email service. With ActiveCampaign, if an individual contact receives three consecutive soft bounce messages, this will be considered the same as a hard bounce.


If your recipients are flagging your emails as spam instead of unsubscribing, some, some email providers will block messages from your email address because you have a poor sending reputation.

Content of your message

Sometimes the content of your emails can cause them to be blocked by mail providers. This can happen if, for example, the content of your email contains a spam-sensitive words or phrases, a spam indicating image, or a link to a blacklisted site. With ActiveCampaign, the summary of your email have its spam score checked.
ActiveCampaign spam check

DMARC checks

Domain-based Message Authentication, Reporting & Conformance (DMARC) is an email authentication, policy, and reporting protocol. It’s used to make sure the sender’s email address is valid and to prevent fraudulent emails. If the address you use to send emails fails the DMARC test, your emails will be rejected.

"From" sender email address

Sending emails using a sender address such as @westpac or @telstra.com.au, can, and probably will, result in bounces. This is because emails not sent from the correct provider indicate a high probability that they’re spam.

Bad email address

These are different to sending to non-existent address at a valid service, such as Gmail. If you send an email to a domain that doesn’t exists, this is considered a bad address. For example, sending an email to an address such as [email protected], will bounce.

Why is preventing bounces important?

It’s important to understand how bounced emails can affect deliverability. If you regularly send emails to addresses that bounce, it’s an indication that you’re not using a valid list of addresses. In time, providers may view any emails from you as risky. Eventually, all your emails may end up recipient’s spam folders.

ActiveCampaign has processes in place to reduce the likelihood of this happening. When a hard bounce message is received, the contact will not be sent any more emails.

How do I find email addresses that have bounced?

From your ActiveCampaign dashboard, select the Contacts icon.
In the upper right hand area, select the Status dropdown. Select Bounced.
You can also view bounced address in campaign or automation email reports.

Contacts with the status ‘Bounced’ will not be emailed and do not count towards the account limit of your subscription.

ActiveCampaign status filter

Why is my bounce rate going up?

It can be confusing to see your bounce rate going up but there are usually some simple reasons.

  1. You’re using a list email addresses that hasn’t been used for a long time. A large percentage of these addresses may no longer exist. Remove bounced email addresses.
  2. Your emails contain words, phrases, or links that attract the wrong sort of interest from spam filters. Use spam checking and change the content of future emails.
  3. You’re sending emails that aren’t relevant to your contacts. They’re flagging them as spam rather than unsubscribing. Send relevant emails and make your unsubscribe link more obvious.

What can I do to reduce my high bounce rate?

No matter what you do, you will always see emails addresses bounce. For example, some people may enter their email address incorrectly. A bounce rate of 0.5% -1% is very normal. However, if you see a high bounce rate, it is likely that it is because adding contacts to your list was not done as usual or you may not be contacting them regularly enough. Below are some strategies you can use to help reduce your bounce rate.

1. Adjust your DMARC settings

How you do this depends on your email provider and your hosting service.

To set this up in ActiveCampaign, there’s a blog post  to help you.

2. Use a double opt-in process

Using a double opt-in has two advantages; first, this will eliminate any invalid email addresses or addresses entered with a typo. Second, the contacts are confirming that they want to hear from you.

You can use ActiveCampaign’s double opt-in process which is enable by default.

If can also create your own double opt-in process using an automation.

3. Add a captcha form

Adding captcha to your forms prevents robots from subscribing to the form and adding spam contacts to your account, whether you have the double opt-in enabled or not.

Be aware, captcha type forms are becoming increasingly unreliable.

To add captcha to your form, go to ‘Forms’ in ActiveCampaign and click ‘Edit’ next to the form. In the ‘Fields’ tab, click on ‘Standard’ and you can ‘drag’ the captcha field into your form.

4. Add a honeypot field

Many spam bots automatically add information to all the fields that they detect. A honeypot field is hidden to the viewer but visible to spam bots. It’s a required field but doesn’t have any data. If data is detected in this field, the email address is treated as spam.

Honeypot fields can be added to ActiveCampaign forms. If you’re using another form builder, such as Gravity forms, you can easily create a honeypot field by selecting an option in the form settings.

4. Send emails regularly

Emailing your list on a regular basis helps you eliminate a small number of bounces at a time as well as engages with your subscribers. Engagement is the key to helping reduce the chances that they’ll flag your email as spam.

5. Set up engagement management automations

There are two automations you can create to help you manage subscriber engagement. The first tracks each time someone opens and email, select a link, or visits your website. When a subscriber hasn’t engaged for a certain amount of time, the second automation sends one or more emails to encourage engagement.

If the recipient doesn’t acknowledge your email and indicate they want to continue to receive your emails, they can be unsubscribed.

6. Use a real-time verification service as an extra security

There are services, such as Briteverify, that can be used to check whether an email address is valid or not. These services are recommended if you receive thousands of registrations per day.

Wrap up

Email bounces are a fact of email marketing life. But they’re just a small piece of the deliverability puzzle. While you should always be looking to get your bounce rates as low as possible you should also be focusing on the greater topic of deliverability.

Keeping any eye on and managing your bounce rate makes sure your emails are reaching your audience and help you to stay on the right side of spam detectors.

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