Hard Bounce vs Soft Bounce for Emails: Know the Difference

Imagine crafting an essential email for your target audience, clicking send, and shortly after, you receive a notification stating, “Your email failed to be delivered.”  

What went wrong? 

Even when you’re sure you’ve set up everything correctly, several factors can lead to your email bouncing back such as server issues, incorrect email address, and more.

In this blog post, we’ll examine all possible reasons that may result in your emails returning in a matter of seconds. Furthermore, we’ll discuss the key distinctions between hard bounce vs soft bounce emails, which are crucial metrics to monitor in email marketing campaigns.  

What Does It Mean When an Email Bounces? 

An email bounce indicates that your email message was not delivered successfully. It is also referred to as a Non-Delivery Report/Receipt (NDR). When it happens, the sender receives an automatic message about the delivery failure. This failure arises from the recipient’s mail server for various reasons (explained below). 

But, why is it essential to find and fix the reasons for the delivery failures? 

It is critical if you want seamless proceedings of your digital communications and generate effective leads over time. 

Type of Email Bounce: Hard Bounce vs Soft Bounce

There are two categories of email bounce — hard bounce and soft bounce — that feature different outcomes.

Hard Bounce

A hard bounce signifies a permanent failure in email delivery. It means that no further attempts will be made to send the message, and you’ll need to find another way to contact the recipient.  

An email hard bounce typically occurs because of incorrect email addresses entered. Alternatively, a recipient’s ISP (Internet Service Provider) may have rejected your email for various reasons.  

Soft Bounce

A soft bounce represents a temporary failure in email delivery. While an email did not go through this time, a server will often try to send it again later. Sometimes, all you need is to be patient.  

An email bounces softly when the recipient’s mailbox is full, when either side hits certain limits, or when an email message is considered too large for acceptance.  

Furthermore, notifications related to out-of-office responses or other autoresponders are mostly classified as soft bounces, but they function differently.

We hope now you’re clear about hard bounce vs soft bounce emails, it’s time to learn about all possible reasons why your emails can get bounced. 

What Causes an Email to Bounce?  

Typically, the bounce notification will provide valuable insights to help pinpoint the reason for the email delivery failure. This may include the following:

The Server Has Blocked Your Email

Advance mail servers reject a multitude of emails they consider unwanted, resulting in deliverability problems and affecting the sender’s reputation. While they are generally correct in their judgments, sometimes spam filters eliminate valid emails without a second thought.  

Generally, this occurs due to insufficient authentication, so make sure you have SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication Reporting & Conformance) configured. Additionally, review the new sender guidelines from Google and ensure your sending practices comply with all the necessary requirements

Additionally, to enhance user experience, ISPs consider past behaviors when deciding whether to accept an email or not. If you frequently send emails that recipients never open, a receiving server might eventually reject them. Therefore, it is advisable to periodically clean your mailing lists and manually unsubscribe those inactive contacts.

Mailbox is Full

Every mailbox has a specific storage limit allocated for incoming and outgoing emails. When this limit is reached, any new message is likely to bounce permanently. In such a scenario, consider reaching out to the recipients through some other methods. 

Another reason for email bounce could be an abandoned account, so you better look for other contacts to approach.

Challenge-response Error

Some individuals set up an extra firewall to verify the senders. When you email such a contact for the first time, you will receive an automatic reply. Typically, you will be required to answer a question or take some action to confirm that you are a legitimate sender.  

Once you complete this, your email will be successfully delivered. However, if you ignore this email and a few days go by, your email will bounce back.  

The only way to prevent this is to complete the required task. The good news is that in most cases, once you prove you’re a genuine person, you won’t have to repeat this. 

The Recipient Doesn’t Exist

This type of error signifies that the email address you entered is invalid. A simple typo could lead to this issue, but it might also be due to a non-existent domain. 

When an email address is invalid, you will often see a 550 5.5.1 server error. For that, you can remove the recipient’s email address from the list. Otherwise, having such contacts in your email list will negatively impact your email deliverability.

If the reason for the rejection is unclear, but you see these confusing numbers, you need to clean your email list or retry with the right email addresses. 

[Also read: 7 Reasons Why Your Email Marketing Strategy Is Ineffective]

How Do You Improve Email Bounce Rate?

The most effective way to minimize the number of bounces is by following the most viable email deliverability strategies:

Organize your lists: Group subscribers based on their activity levels and engagement. This allows for personalized content that is more likely to resonate and less likely to be overlooked.

Manage email size and content: It’s important to keep track of your email content, including monitoring the size of attachments and images. If your emails are frequently soft-bounced due to being oversized, think about compressing attachments or providing links.

Actively manage bounces: Employ features in your email platform, like list management, to automatically remove addresses that consistently lead to hard bounces. Establish guidelines for how many times you will attempt to resend emails that soft bounce before deciding to remove them.

Consistently review server performance: Soft bounces can often happen due to server malfunctions or congestion. Ensure that your email service provider maintains peak server performance and reliability. Regular checks can help pinpoint trends or recurrent downtimes, allowing you to better strategize your email campaigns.

Maintain clean lists: Eliminate inactive subscribers, invalid email addresses, and non-responsive users from your list. Utilize automated tools to detect and remove these emails efficiently.

Send confirmation emails: Always send a confirmation email that requires new subscribers to verify their email addresses. This additional step helps you confirm the subscriber’s interest, leading to loyal customers.

Dispatch welcome emails: After confirmation, send a welcome email as part of the initial interaction. This establishes the tone for the relationship and can enhance long-term engagement and deliverability.

Monitor regularly: Keep a vigilant eye on your email delivery and bounce rates. Review trends over time to identify when your campaigns are experiencing deliverability challenges.

Address issues: If you detect a sudden rise in bounce rates, investigate and resolve possible causes, such as problems with your email server or adjustments in email content that might trigger spam filters.

Achieving high email delivery rates can be difficult, but it is manageable if you are familiar with the process and implement the right strategies.

Wrapping Up

Understanding hard bounce vs soft bounce emails is crucial for optimizing your email marketing strategy. By regularly monitoring bounce rates, improving your email list, and following best practices in deliverability, you can significantly reduce bounce rates and improve the chances that your emails reach the intended inboxes. 

Moreover, implementing authentication protocols, like SPF, DKIM, and DMARC, actively managing inactive or invalid contacts, and sending confirmation emails can go a long way in building trust and enhancing engagement with your audience.

Remember, effective email marketing is not just about sending messages but about establishing a sustainable connection with your audience. Your efforts to maintain clean lists and personalize email content can help you avoid potential deliverability issues and ensure a successful email marketing campaign.

[Also read: 9 Best Email Marketing Tools Every Marketer Should Know]