Soft Bounce Vs Hard Bounce: What's The Difference?

Understanding the difference between the terms soft bounce" and "hard bounce" is important for anyone aiming to run a successful campaign. Both terms relate to issues that can occur when sending emails, and each can significantly impact your hard bounce rate. Identifying and addressing these issues is important to maintaining a healthy email list and fostering strong relationships with your recipients.

In this article, we will explain the key differences between soft and hard bounce. We will also explore the various causes of these bounces and offer insights into how you can improve email deliverability and email bounce rate and ensure your email messages reach their intended recipients.

What Is a Soft Bounce?

In email marketing, a soft bounce is a temporary failure in email delivery. The email gets as far as the recipient's mail server, indicating that the email address is valid. However, the email message bounced back before reaching the customer's inbox. Several factors contribute to soft bounces, affecting your overall effort to improve email deliverability rates.

Soft bounces can happen due to the following reasons:

• The recipient's mailbox could be full.
• The receiving server may be down or overwhelmed with messages.
• The email might be too large to process.
• The recipient's settings may reject the sender.
• The content could be flagged as suspicious or spammy.

Understanding these factors is crucial for addressing issues related to what is a soft bounce and for lowering your hard bounce rate.

What Is a Hard Bounce?

Unlike a soft bounce, a hard bounce is a permanent failure in email delivery. This typically happens when the customer's email address is either invalid or no longer in use. Such failures are detrimental to your email campaigns and can inflate your hard bounce rate if not addressed promptly.

Hard bounces can occur due to the following reasons:

• The email address is invalid or contains a typo (e.g., "gnail" instead of "gmail").
• The domain name is invalid or no longer exists.
• The email server for the domain is not set up properly.
• The email address has been deactivated or deleted.

Hard bounces are particularly challenging because Internet Service Providers (ISPs) will send back response codes indicating why your email failed to deliver. These response codes can vary between different ISPs and mail servers, adding another layer of complexity to understanding what is a hard bounce.

Hard bounces are permanent delivery failures, usually due to an invalid email address or non-existent email address. They need immediate attention, as they can significantly impact your hard bounce rate and overall email deliverability.

Different Causes of Soft Bounces and How to Fix Them

Below are some common reasons for soft bounces and suggested solutions for each issue:

1. Mailbox Full

A full mailbox can sometimes cause soft bounces. If you've been sending emails to a customer that were previously delivered but are now failing, the email is temporarily categorized as a soft bounce by the ISP. After 2-3 days, if delivery continues to fail, it may be classified as a hard bounce.

How to Fix:

• Notify your customer that their mailbox is full.
• Ask if they have a new email address.

2. DNS Failure

DNS failure happens when an email can't be delivered due to DNS issues at the recipient's end. The issue could be a down server, a typo in the setup, or a non-existent domain.

How to Fix:

• Try resending the email in a day or two.
• Reach out to your customer through another medium to confirm their email address.

3. Challenge-Response Error

Some email filtering services send a challenge-response reply to filter emails from unknown senders. If the challenge isn't completed correctly, the email isn't delivered.

How to Fix:

• Implement permission-based email marketing. Use a double opt-in process to add customers to your mailing list.
• Test your email campaigns for spam triggers before sending them.

4. Vacation/Out of Office/Auto-Reply Emails

Auto-reply emails usually indicate the customer is temporarily unavailable, meaning the email will likely be read at a later time

How to Fix:

• You generally don't need to do anything in this case. Your customer will eventually see the email once they resume checking their email.

5. Other Errors

Sometimes, the reason for a soft bounce can't be determined, usually due to a technical issue like a timed-out connection.

How to Fix:

• Reach out to the customer to check for a new email address.
• If the problem persists and the email address is verified, consider seeking professional help to troubleshoot the issue.

Different Causes of Hard Bounces and How to Fix Them

Understanding hard bounces is just as critical as understanding soft bounces when it comes to maintaining a healthy email list and boosting the effectiveness of your email marketing campaigns. Here, we will explain the different categories of hard bounces and provide ways to fix each specific cause.

1. Recipient Does Not Exist

When the Internet Service Provider (ISP) reports that an email address doesn't exist, this is akin to a post office declaring that there's no such person at a given address. Persistently sending emails to non-existent addresses can tarnish your sending reputation, affecting your business and your email service provider, like Constant Contact.

How to Fix:

• Double-check email addresses for obvious errors.
• Reach out to the customer through other channels to verify or update their email address.
• If the issue persists, it's wise to remove the email from your list or contact support for further troubleshooting.

2. Mailbox Full

This differs from the soft bounce category for a "Mailbox Full." The full mailbox is a consistent issue, indicating that the email address may have been abandoned. This is commonly seen in special-purpose email accounts that people no longer use.

How to Fix:

• Contact the customer to inform them that their mailbox is full.
• Ask if they have a new email address.
• Remove the email address from your list if it continues to bounce.

3. Blocked Email Address

ISPs may block email addresses due to suspicions of spam or other security policies. This is especially crucial when it comes to your sender reputation and can involve aspects like DMARC, DKIM, and SPF authentication failures.

How to Fix:

• If the ISP is a smaller domain, try contacting them to resolve the issue.
• For blocked bounces from larger domains like Yahoo or Gmail, it's advisable to contact support for resolution.

4. Rejected by Spam Filters

Sometimes, an email or its subject line contains content that triggers the spam filters of the ISP. If a customer has previously marked your emails as spam, all future emails will likely end up in their spam folder.

How to Fix:

• Re-evaluate your email frequency and content for customers who frequently show up as "did not open" in your reporting.
• Run a spam check before sending emails to ensure they don't trigger spam filters.

Conclusion

In this article, we've explained the different causes of hard and soft bounces in email marketing and how to address them. These issues, if not handled correctly, can impact your email deliverability and, subsequently, the success of your email campaigns. Implementing the solutions we've discussed can go a long way in ensuring your emails reach the intended inboxes.

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