Everything You Need to Know About Email Bounce Rates

Bounced emails are literary the dirty linen of any email marketing campaign. You can ignore them for a while, but sooner than later, they will start piling up, and eventually degenerate into a problem. And though managing email bounces is not the most exhilarating part of your marketing strategies, building a clean list is fundamental to launching a successful email marketing campaign and ultimately realize impressive response rates. The problem is, most marketers do not understand the basics of email bounce rates, making it hard to launch productive marketing campaigns. Fortunately, that’s where we come in. Whether you are a novice or a veteran marketer, this site is your portal into the world of efficient email marketing. In this particular post, we have gathered information every marketer needs to know about email bounce rates; from why emails bounce, how to handle bounces, how to achieve a low bounce rate, to why it is important to maintain a clean list of emails.

What is an email bounce?

Well, it is no rocket science! Just like the name goes, an “email bounce” occurs when an email cannot be delivered to the recipient’s email address. To be precise, it ‘bounces’ back to the sender as a result of several underlying problems. These can be transient, permanent, irreparable or solvable. Whenever such a bounce occurs, a message is sent back from the receiver’s mail server with information why the delivery failed.

Why do emails bounce?

Whether you are sending emails via a personal SMTP server or an email service provider, they are all subject to SMTP commands which determine whether an email is accepted or rejected by the receiver’s mail server. Technically, all emails have to successfully pass through several verification phases before finally being delivered to the intended recipient. This is how it happens.

After sending emails to recipients, they are first delivered to your SMTP server. And even if you are using third-party mail service providers, the messages are forwarded to their respective SMTP servers. They are then queued as your SMTP server attempts to communicate with the recipient’s mail service provider. The receiver’s server then determines whether it is going to accept or reject the mail. If it accepts, the message is considered sent. Otherwise, if the receiver’s mail server has predetermined for whatever reason that it is not going to accept the message, the email is considered as rejected. It will then bounce back to the sender with information why the email was declined.

Understanding email bounce metrics

1.    Summary report

After sending emails, a bounce summary report is going to be generated. It contains a list of the emails that bounced and also a report on why the delivery failed. Each email address is then classified as a soft or a hard bounce. This denotes whether the underlying problem is temporary or permanent.  We will be looking at these two categories later in the article.

2.    Bounce domains

The bounce domain metric indicates the number of emails that have bounced from a specific domain. This information is very useful when it comes to determining whether there might be a problem with a certain domain. If you notice a big number of emails bouncing from one domain, it could be an indicator that they are being blocked by the Internet Service Provider’s server.

You see, ISP’s check the source of each email. If it detects that you are sending several emails at a go, your emails might be rejected on the assumption that you are a spammer. If you realize that most of the emails to certain domains like @outlook.com or @gmail.com are resulting to bounces, you might have been labeled a spammer. In such a scenario it is best to contact a reputable email validator for advice on how to move forward with your email marketing campaign.

3.    Ideal bounce rates

This is perhaps the most important metric to monitor whenever you are conducting an email marketing campaign. The bounce rate is calculated as total the number of bounced emails divided by the total sum of emails sent during the campaign.

This rate is determined by the quality and validity of your mailing list. A low bounce rate is a strong indicator of a healthy permission bases list full of active and happy subscribers. On the other hand, a high bounce rate could be a pointer to a poor and inactive subscribers list. The problem could be with the way the list is being managed or how it was obtained.

If your business has a healthy opt-in list, you should be getting a bounce rate between 2 and 3 percent. If you are getting anything higher, it is very imperative to determine why and take action to minimize the bounce rate. In most cases, if your server regularly receives a bounce rate beyond 3 percent, you could end up being suspended or being labeled as spam by major internet service providers.

Soft bounce vs. hard bounce: what does each mean?

Whenever an email bounces, it is categorized as either a hard or soft bounce. Let’s have an in-depth look into each

1.    What is a soft bounce in email marketing?

In simple terms, a soft bounce refers to a situation where the email temporarily fails to reach the recipient’s inbox. It implies that the email address is valid and it was accepted by the recipient’s server, but the message bounced back before reaching the receiver’s inbox.

Soft bounces can occur as a result of several problems. For instance, the receiving server could be temporarily down, the message could be too big, the recipient’s inbox could be full, spammy or suspicious information was detected in the message or the receiver’s email settings do not allow emails from your address. A soft bounce is an indication that the recipient’s email is valid. If you never made it delivering in one marketing campaign, you can try your luck during the next.

2.    What is a hard bounce?

This is a permanent delivery failure. Whenever you get a hard bounce report, it means that the recipient’s email is no longer in use or that it is invalid. Most likely, it could have been wrongly typed or the email’s domain no longer exists. If you are sure that the hard bounce never occurred as a result of a correctable typo, all emails under this category should be removed from your subscriber’s list. They can also be exported to into a suppression list to prevent them from reimported into your active mailing list.

Reimporting hard bounced emails into your active subscriber’s list will have a negative impact on your deliverability. Spam filtering systems and ISPs record bounces and they could be used to negatively judge your server in future whenever an invalid address is emailed more than one time.

Tip: It is also very important to understand that different servers interpret bounces in a different way. What could be classified as a hard bounce in one server could be categorized under a soft bounce in another.

When does a soft bounce become a hard bounce?

This largely depends with your email service provider. However, in most cases, an email address that returns 5 soft bounces with no clicks or opens during a specified period of time is automatically converted into a hard bounce. If the recipient interacts with the emails later, the recorded number of soft bounces for that address is reset to zero.

How to prevent email bounces?

1.    Use confirmed opt-in

A confirmed opt-in is perhaps one of the best ways to collect valid emails from interested subscribers. By making sure that people who subscribe to your emailing confirm their email addresses, you eliminate the probability of erroneous emails finding their way into your mailing list. Apart from significantly reducing the bounce rate, this method also ensures that you get an interactive and active subscriber list. This way, the audience becomes more engaged, increasing the chances of a conversion.

2.    Don’t use a free domain send-from address

Free domains email addresses like outlook, Hotmail and Google might end up failing a DMARC check. If this happens, all of your emails will automatically bounce and if they are received, the recipient’s server is going to route them into spam or junk categories, and the intended person will never get the chance of receiving it. If you are after better results, send your emails from an authenticated business domain. This prevents emails from being classified under the spam or junk category. This will significantly improve your email deliverability and also boost your bounce rate.

3.    Send frequently and consistently

Contacting your subscribers regularly and consistently is an integral ingredient for a successful and productive email marketing campaign. In as little as 6 months, subscriber lists can become stale. I mean, disengagement for a very long time could result in bounces or spam reports.

Start by sending your subscribers a welcome message, then regularly send them relevant and useful information. Subscribers also regular change their email addresses or leave old ones for new ones. By maintain constant communication with them, interested ones will always update their emailing information and this will not result in high bounce rates. If left for so long or contacted sporadically, subscribers who change or abandon their email addresses will not the chance to update their contact information.

There is no holy Mary grill guide with the number of times of you should contact your subscribers. However, with a couple of emails monthly, you should be able to establish a lasting relationship with your subscribers. Just contact them regularly with what they want to hear.

4.    Include a preference center

Always include a preference center where subscribers can update their contact information when need be. This will not only prevent bounces when subscribers change emails or abandon old ones, but also give them the autonomy to decide the email address that should receive your newsletters. In the long run, this will cultivate trust between you and them.

5.    Use a List Verification Service or an online Email Validation API

If your list has been receiving high bounce rates or has been dormant for some time, it will pay off to use an email verification service. Such a service will help you identify and get rid of invalid addresses before launching your next marketing campaign.

Removing invalid addresses is not that simple. That’s the reason it is wise to contact a professional company to help you out. When validating emails, some might be classified as unknown or risky. In such a situation, completely removing them from your subscriber list might not be the best option. Staggering sends should be done to ensure that they are indeed invalid.

This should be done by adding a few of the suspicious emails in your emailing list then look at what happens. If they end up to be valid, you can go ahead and permanently add them to your mailing list. Otherwise, you should get rid of them. Do not use a large number of them at once because this will destroy your bounce rate, which will negatively affect your deliverability. Spam filters and internet service providers pay close attention to bounce rates and the attempts to send emails to invalid addresses. Eventually, you could end up being spammed or blocked altogether.

By getting your list verified, you minimize the risk of damaging your reputation by only sending emails to valid addresses.

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6.    Be vigilant and monitor your results

As with deliverability and engagement, the longer you leave bounce issues unsolved, the more damage you cause to your reputation. Therefore, monitor your campaigns closely and whenever you notice a spike in your bounce rate, take action immediately. Perhaps, a particular domain could be the problem or some emails could have become invalid.

It is also important to double check your email sources, improve your sign up form, and frequently update your subscriber’s list. Make sure that you always send your emails with an authentication and also from the same domain. If you are not sure why you are receiving a very high bounce rate, contact an email verification company for advice on how to proceed.

7.    Validate your emails

Validating your emails (using services like online API that validates your emails in real-time) is very important in an email marketing campaign. Failing to validate your emails will most likely end up in junk folders or bounce back to you because receivers cannot verify the legitimacy of your sends. By authenticating your domain, you give authenticity and legitimacy to your emails. Receiving ISPs and spam filters will no longer categorize your emails as junk. This will significantly boost your bounce rates and also improve the deliverability of your emails.

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Email Bounce Rate FAQ

Below, we have provided answers to some of the most common questions regarding email bounce rates. If you feel that your issue is not addressed, go ahead and contact us.

How long does it take for bounced emails to reflect on campaign summary reports?

Under most situations, bounced email addresses reflect in your report a few minutes after being sent to recipients.  Typically, hard bounces are first to appear, while soft bounces can take up to 12 hours to appear in your report

Does a bounce imply that the email has landed into the recipient’s junk folder?

Emails that bounce do not go as far as reaching the recipient’s folder. If it landed in the recipient’s junk folder, it would never have appeared under the bounce summary report. There is also no notification in such an event.

I have an email address under hard bounce, but I am sure it is valid. What could have happened?

In such a case, the recipients SMTP server could have sent the wrong delivery report.

Some subscribers never received my email, through their email address are not listed as bounced. What could have happened?

This could be due to the following reasons:

  •    The receiver’s internet service provider might have determined that the email could be spam.
  •    Your email service provider’s system could have been blacklisted by the subscriber’s ISP.
  •    The receiver has strict spam controls. For instance, he/she might be blocking emails from unknown senders, resulting in your email landing into his/her junk folder.

If an address doesn’t appear under the bounce summary report, can I presume that it was successfully delivered?

Email addresses can bounce and not show up under the bounce rate report if the ISP or the mail administrator does not return an error message. However, this rarely occurs.

Final words

Truth be told, high bounce rates destroy your deliverability and also compromise your sender reputation, risking your account with your email service providers being blocked or shut down. Therefore, be sure to use an email validation service to ensure that the emails you are sending are all valid and avoid high bounce rates for a productive email marketing campaign.

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