Email Deliverability

What are Bounced Emails? And How Can Senders Limit Them?

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When you send an email and it’s returned with either a soft or hard bounce (more on that later), you need to take immediate steps to ensure your email deliverability doesn’t suffer. While a few of these emails won’t set your performance back too far, they can still create lasting damage to your brand if you don’t diagnose the issue.

To improve your deliverability and ensure every email you send lands safely in the inbox, let’s explore what causes emails to bounce—and steps you can take immediately to reduce your email bounce rate.

What are bounced emails?

A “bounced” email means your message could not be delivered to its intended recipient. You’ll receive a notification that your email bounced shortly after sending it, and you should immediately assess if it is a lasting issue or something that can be fixed easily.

There are two specific types: hard bounces and soft bounces.

Hard bounce

A hard bounce email indicates a permanent issue, meaning the address you tried to send to either doesn’t exist or you can’t send emails to it (which is a sign of a much bigger problem).

If you receive a hard bounce after sending an email, remove the address from your outreach. If you keep sending emails to this address, you’ll weaken your overall email deliverability and sender reputation.

Soft bounce

A soft bounced email, however, is a temporary issue that can be fixed. It means the intended recipient’s email address exists, but there’s an issue with either their mailbox or your message that needs to be fixed before the email will fully deliver.

What causes emails to bounce?

In some cases, your email bounce notification will tell you specifically why the message was not delivered. Otherwise, you’ll need to diagnose the issue yourself.

A hard bounce can happen if:

  • Your recipient’s address is misspelled
  • The recipient’s domain does not exist
  • Your message was blocked by the receiving server

If you don’t see a typo in your recipient’s address and are sure the domain exists, it may have been a soft bounced email.

A soft bounce can happen if:

  • The recipient’s email server is currently down or overloaded
  • You’re sending an email or file size that is too large
  • The recipient’s mailbox is full

A soft bounce may resolve on its own as the message keeps trying to deliver itself. Otherwise, you will need to reduce your email file size to overcome the soft bounce.

Do email bounces impact deliverability?

The number of email bounces you receive ultimately hurts your sender reputation. If left unchecked, they will cause more of your messages to land in spam or become blocked entirely.

Unless you’re consistently sending messages with a large file size, soft bounce emails are not a major cause for concern. Hard bounced emails, however, require immediate action as they can do serious damage to your sender reputation and deliverability if left unaddressed.

How can you calculate your bounce rate?

You can calculate your email bounce rate by dividing the number of bounced emails received by the total number of emails sent, and then multiplying that number by 100. This will give you your bounce rate percentage.

For example, if you sent 300 emails and 15 bounced, then you have a 5 percent bounce rate (as calculated with (15/300) x 100).

Most email marketing and email deliverability tools will automatically calculate your bounce rate as you engage in outreach and track your bounce rate over time. This is incredibly helpful for quickly identifying a potential issue with your strategy.

Tips to help you reduce your email bounce rate

What can you do to lower your email bounce rate? Luckily, it’s fairly easy to catch emails before they bounce (or fix them if they do) by following these tips:

1. Authenticate your email

The first step for improving your email deliverability is to authenticate your email. There are three specific email authentication standards you need to implement:

In tandem, each of these will improve your email security and limit the chances of your email being used in phishing and spoofing attacks.

2. Verify your email domain

Before you send an email marketing campaign, you should verify that your recipients’ email domains exist. There are many common mistakes that teams make, such as confusing a .ai address for a .com address, or using a company abbreviation when its email domain is its full name.

Consider implementing a tool to verify if an email domain exists before you send your email. Or, manually review your outreach list and create a document that identifies domains that are commonly used incorrectly, such as vs vs

3. Avoid sending spam-like emails

If your emails sound like spam, then your recipients will mark them as such. Use clear and relatable language for your audience. Avoid using language that’s too salesly, and try not to rely on common spam triggers like “free” or “act now!”

4. Keep track of your email deliverability

Your deliverability is a primary signal of your email program’s health.

If you have poor email deliverability and fail to correct your practices, you could be blocked from sending messages entirely and need to completely rebuild your infrastructure—which no one wants to do.

Monitor your email deliverability, and if your bounce rate begins to rise significantly, pause any outreach until you understand what the problem is.

5. Be consistent with your email activity

Your customers sign up to receive your emails because they want to hear from you. Be consistent with your outreach (but not too aggressive) so your buyers remember your brand and why they shop with you.

If you only send emails during peak shopping seasons, your customers may have forgotten about your brand during the off-season. So, when you try to send to them again, your messages will seem unsolicited—causing them to unsubscribe or mark you as spam.

6. Make sure your email list is permission-based

To reduce unsubscribes and spam complaints, it’s important to make sure everyone on your outreach list has expressed explicit permission to receive your emails.

A great way to ensure consent is with double opt-in confirmation. This is when a new subscriber receives an email asking them to confirm their subscription before continuing to receive emails from your brand.

7. Maintain good email list hygiene

Improving email list hygiene is the ultimate way to boost deliverability and stop emails from bouncing. To improve list hygiene, regularly scrub your CRM data to confirm entries are accurate and there are no duplicate records. If you receive a hard bounce email, remove it from your lists immediately. Good list hygiene will also help you avoid sending messages to spam traps.

Say goodbye to bounced emails

Bounced emails can take a serious toll on your deliverability. Be sure to follow these tips to keep them at bay, improve your deliverability, and protect your bottom line.

Curious to learn how else you can improve your deliverability? Check out our list hygiene guide to discover the common culprits of poor list hygiene, how they’re killing your email performance, and best practices to help you become a best-in-class sender.