Tag Archives: hard bounce

This is a guest post from Brian Dayman at Kickbox.

So you’ve decided to migrate to another ESP.

Whether it’s through improved email workflow, more complex metrics tracking, better segmentation, or anything in between, taking on an ESP migration can help you connect with more customers and take your marketing to the next level.

But before you can reap the benefits of a new ESP, you’ll need to go through the migration process, which has the potential for a lot of headaches if done with a “fly by the seat of your pants” approach.

Platform migration

No matter your industry or marketing team’s size, there’s a need to manage a myriad of migration tasks like galvanizing a team of stakeholders, managing the project, learning about your new technology, mapping, and, perhaps most importantly, cleaning up your data.

Not the most glamorous task, but one of the most critical

To be honest, taking responsibility for cleaning up a marketing database isn’t the most glamorous of jobs to take on. However, it’s necessary if you want to make the migration process as seamless as possible and reap maximum rewards from it.

Migrating ESPs is a prime opportunity to make sure your data gets the attention it doesn’t always receive. Separate from standard list hygiene, preparing for platform migration is a perfect time to conduct a deep clean of your database. And the reasons for doing so are far from arbitrary.

Cleaner data now is more ROI later.

The truth is that, from small to large, all companies have dirty data (up to 25% of their entire marketing database).

This is especially true of those with older subscriber databases or using multiple channels to collect data.

For example, an ecommerce marketer with multiple campaigns for each product or an agency with multiple clients’ lead data to manage. On average, organizations use 3.8 channels to collect data, each potentially incorporating multiple points of capture.

At Kickbox, we’ve found that 12.5% of email addresses entered on signup forms are initially invalid due to misspelling or attempting to use fake addresses.

Compounded over time, the database decay can cause deliverability and email ROI to take a hit when sending through your new ESP.

Additionally, your new ESP will often analyze your mailing lists for quality concerns when migrating to their platform, so it’s best to be prepared for that by cleaning up any risky data that could be hiding spam trap risks or other IP blacklisting concerns.

Even if your lists are not flagged during the migration process, cleaning up your database can still optimize performance and mitigate any issues that’ll lead to lower inbox placement and wasted marketing dollars in the long term due to poor sender reputation.

And, with increasing data privacy laws and evolving anti-spam technology used by ISPs, it’s more important than ever to keep your relationship in good standing with both senders and subscribers alike.

The cleaner you get your data now, the more benefits you can reap later. One of our high-volume sender customers, albeit through a separate process from a platform migration, recently shared their results for bounce rates for their transactional email after incorporating some data hygiene practices.

See your industry’s average bounce rate here.

Bounce rate graph showing bounce rate, hard bounce rate, and soft bounce rate: You'll need to know your rates if you're considering platform migration.

As they taught us in the military: make your bed first thing in the morning, because, when you come back from a day of work and you’re tired, it’s going to be much harder to tidy things up. In other words, be considerate of your future self.

To help you with your approach to data preparation, here’s a three-step process to follow when preparing your data for your new ESP as efficiently and painlessly as possible.

1. Commit to being the marketing data champion of your team.

Depending on the size of the marketing team you’re working with, there’ll often be a team of internal stakeholders to make the migration happen.

For example, an engineer will often own the technical parts of the migration. A business operations leader might make decisions on which data is most critical to maintain and how to organize it.

The marketing leader will often own the email database, as well as the messaging and segmentation within the new ESP. A project manager might ensure all roles and tasks are owned and track the deadlines.

As a marketing data champion, you’ll often be dealing with two main categories of data: event data and subscriber data.

Where event data is associated with actions taken within individual campaigns like those associated with specific products, subscriber data is personal data, and is foundational to your marketing. After all, the only profitable contact in your database is one that you can reach.

Before kicking off your subscriber database cleanup, be sure your role as data champion is defined among your team.

You should coordinate with other stakeholders to ensure you can surface future questions about field mapping, integrations, and business goals as you organize the marketing database in preparation for ESP migration.

2. Identify the good, the bad, and the ugly.

Before we can begin the cleanup process, we need to get a gauge on the health of our database and unveil risky data that’s hidden within it.

But defining what’s risky can be challenging if you don’t have a clear definition of what a low-quality address is, aside from engagement rates.

Start with deliverability instead of time since last engagement.

Conventional marketing knowledge tells us to treat unengaged subscribers as risky data. And, while there’s definitely a correlation between unengaged legacy subscribers and risks like spam taps or future spam complaints, simply flagging emails as risky by using only a time-based standard can lead to missed opportunities.

In some contexts, sending an email to a deliverable contact will have a beneficial long-term impact even without a recent open or a click.

In The Email Addiction subscriber study, it was found that over 50% of unengaged subscribers are either waiting for the right offer (37%) or because they expect to buy from the brand again. (24%).

Survey on unsubscribing: It's important to know what your subscribers are doing when you perform platform migration, especially to another ESP.

Additionally, data champions don’t always have full insight into the health of legacy email data if they weren’t directly involved in its acquisition (e.g., tradeshow leads uploaded by field reps or leads from another marketer’s campaign).

That’s why it’s so important to start the database cleanup with the Deliverability-Based Method.

As opposed to a time-based method that tosses out emails that haven’t been engaged in a certain timeframe, the Deliverability-Based Method uncovers risky data based on how likely these emails are to reach the intended recipient.

This is done through email verification and serves as a lower-risk method for testing emails than loading them into your new ESP and hitting send.

If verifying legacy email data, then list or bulk verification will be used, and can often be done through integrations with your old or soon-to-be-old ESP to gauge the health of your current email lists. Soft-bounced lists should be included in this process as well.

Need deliverability resources? Get the collection.

Once verified, high-quality deliverable email addresses will be distinguished from risky email addresses that could cause issues with the ESP migration process or performance after migration. Examples of risky addresses are:

  1. Accept-all: the domain accepts all email you to send to it, even if the email address isn’t valid
  2. Disposable: one-time email addresses often used to receive initial communications from a service (such as an activation email) and are discarded.
  3. Role: an email address that’s associated with a team or job function instead of an individual.
  4. Free: potentially risky. Free email such as Yahoo and Gmail can receive lower open and deliverable rates in certain contexts, although B2C businesses generally benefit from accepting free email services.
  5. Undeliverable: low quality—the email address doesn’t exist or is syntactically incorrect.

Once you’ve verified a list, you should be able to see the health of your marketing database, both by individual lists and at a glance.

Verification graph showing verified activity and deliverable content

By unveiling the deliverability of email addresses in your database, you can have an idea of which contacts are worth re-engaging and potentially preserve the value of the list you’ve worked so hard to build.

Single out the other obvious culprits.

In addition to identifying risky deliverability statuses of your database’s emails. Duplicates, redundant data fields, and hard bounces should also be removed.

This is where exporting your lists and rolling up your sleeves will be necessary, but make the actual data cleanup that much easier.

Now that you have your quality and risky email addresses organized in separate bins, you’re in a much better position to take the next step to shaping up your database for migration.

3. Clean up the dirty data.

Once you’ve identified the good, the bad, and everything in between, it’s time to do the actual cleanup. The cleaning of your database for your migration involves two parts: making decisions on what to prune and preparing your suppression lists.

Decide what to prune.

Undeliverable, unsubscribes, and hard bounces should be a starting point for flagging what should go onto your suppression list.

From there, it’s time to look at your current and new ESP’s segmentation options, analyze the business impact of each deliverability category, and decide which ones should be mapped or suppressed.

While you don’t have to sit on a throne like Cesar and give the thumbs up or thumbs down to each segment or category, consideration should be given to the business impact of each segment before deciding which to keep.

This is where Step 1 comes into play and coordinating with other stakeholders (if there are any) to decide what subscriber data to carry over based on your audience, product, industry, and business goals.

Update your suppression lists.

Now that you’ve done the heavy lifting of identifying and deciding what data to prune, it’s time to clean up your database. This should be done through your suppression lists.

When pruning your contact list, simply deleting the contacts isn’t enough. Instead, contacts should be added to a suppression list as a failsafe to stop the email address from being re-engaged and to comply with anti-spam laws.

Hard bounces are automatically added to suppression lists, so be sure to include those from the ESP you are migrating away from.

Wrap up

Once you’ve cleaned up your marketing database, your team will be ready to take on other possible steps in the migration process like domain setup, authentication, IP warmup, and perhaps further tweaking your segmentation strategy.

The process should be a gradual one, and could be more complex based on your database size and your business goals. But, with a clean database, getting up and running with successful campaigns will be much less of a headache and you’ll be in a position to maximize your email marketing with your new ESP.


Brian Dayman is a Marketing Manager at Kickbox

Brian Dayman is a Marketing Manager at Kickbox, a technology provider that promotes email best practices to improve deliverability. The mission: ensure customers with opt-in contacts get their message to the inbox and to prevent all the rest from hitting send.

Bounced email addresses can be one of the most frustrating aspects of email marketing. A bounce means your reader didn’t receive the information they wanted and you wanted them to see.

There are many things you can do to help your emails make it to your readers’ inboxes.

Read on to discover the differences between hard and soft bounces, why they occur, and how to prevent and resolve issues with high bounce rates.

What is a bounce rate in email marketing?

When it comes to an acceptable bounce rate, email marketing metrics work a little differently. Unlike open rates and click-through rates, you don’t want your bounce rates to be high. In fact, the lower, the better.

Bounce rates measure the percentage of how often your emails get “bounced” back to you. In other words, the email cannot reach the intended recipient and, therefore, must be returned to the sender with a notification of its bounced status.

If this sounds familiar, it’s because it’s the same way that physical mail works. If there’s something wrong with the address, it gets redirected to the return address.

In case you’re confused, this kind of bounce rate is totally different from a web page’s bounce rate. A bounce on a web page occurs when a user arrives at the site and leaves without interacting with anything.

What does it mean when an email has bounced?

The reasons can be permanent or transient, solvable or irreparable, so, when a bounce occurs, a return to sender message is sent from the recipient’s mail server to help diagnose the issue.

An email could be bounced for many different reasons. One of the most popular reasons is that your recipient no longer has that email account or it has been inactive for a long period of time and was deleted.

For that reason, you want to make sure you keep your mailing list clean, or your bounce rate will rise and your email reputation will fall. A low email reputation will put you in the sights of the spam filter, which creates a vicious cycle of non-engagement.

Alternatively, emails can be bounced if the email server is under construction, which is known to occur with email addresses attached to business or organizations. Your email can also be bounced if the recipient puts you on a “blocked” list.

In fact, there are so many reasons for bounce rates that they actually have categories. Bounces are usually categorized as either hard or soft, depending on how series the problem is.

What’s the difference between a hard and soft bounce?

Hard bounces are permanent delivery failures. This could be as a result of an invalid, erroneous address, an outdated domain, or an address that has fallen out of use. At Campaign Monitor, if an email is marked as a hard bounce, it’s automatically suppressed and won’t be sent to again.

Soft bounces are temporary delivery failures and can occur for a variety of reasons. There may be a temporary issue with the receiving server, the recipient’s mailbox may be full or the receiving server may have identified an email as too large.

There are many reasons why soft bounces occur, but, by carefully maintaining your list and ensuring your data is sourced with opt-in permission, you can mitigate the potential for these kinds of bounces.

In most cases, an address will soft bounce five times before being automatically converted by Campaign Monitor into a hard bounce.

If you’re seeing bounce rates above the 2% industry standard, continuing to send to those addresses without action and investigation on your part will damage your sending reputation with receiving ISPs and will degrade the deliverability of your future sends.

What is a good email bounce rate?

It’s important to understand that a small number of bounces are to be expected over the lifetime of an email subscriber list. Addresses are changed or abandoned by their owners, people change roles or jobs, and temporary delivery issues can result in a small number of bounces too.

The benchmark for bounces is less than 2%. Anything above a 2% bounce rate for your email campaign is worthy of your attention. If you’re seeing bounce rates over 5%, or even as high as 10% or greater, this suggests a significant problem that you will want to resolve.

While these are the average bounce rates, it’s important to know that each industry has its own unique bounce rate. This is because each industry targets a particular demographic, and demographics have their own behavioral patterns.

For example, the average bounce rate for the retail industry was as low as 0.69% according to original Campaign Monitor research. Advertising and marketing agencies had a higher (but still healthy) bounce rate of 1.29%.

While it’s good to know the average bounce rate among all industries, it’s better to have the number for your particular industry. That number will be a better guide as to where your own bounce rate should be.

If you want to know the most recent bounce rate for your specific industry, you can find it here.  You’ll also find the average rates for opens, click-throughs, and unsubscribe rates, which are all related in some way to bounces.

How do I reduce email bounce rate?

Now that we’ve covered why email addresses bounce, you’re probably asking yourself if you can do anything to prevent high bounce rates. Although there are some aspects of email delivery that are out of your control, there are still plenty of things you can do to make sure you have a low bounce rate.

Use permission-based, opt-in data

It all starts with your list. Lists that are not created with opt-in permission of each individual recipient are more likely to see issues with high bounces and invalid addresses.

Ensure you are in compliance with our policies, that your lists are built with permission, and that your signup forms include an opt-in checkbox.

Non-compliant sources such as scraped, purchased, or third party email addresses are strictly prohibited from use at Campaign Monitor, and will always see issues with high bounces, low engagement, and deliverability.

The key to the success in email marketing is the strength and compliance of the list. Use only opt-in, permission-based lists that comply with our policies and best practices and you will already be on your way to engaged, active lists with low bounce rates.

Be smart with incentivized signups and competitions

Common sources of email addresses that see high bounces are competition forms, WiFi signup pages (where you get free WiFi for signing up), or other incentivized signup forms.

Sometimes, people are tempted by a competition prize or want to sign up to use WiFi, though they do not wish to be added to a mailing list. These people use fake addresses or abandoned mailboxes in order to take advantage of the offer without receiving future emails.

The first step is to be compliant with our policies and ensure that you have an opt-in checkbox on your signup form so that only people who check the box and want your emails are added to your list.

Be clear with your subscribers about what they will be receiving and let them know they can unsubscribe at any time.

Show the value of your newsletter at signup and make sure that your content is valuable and relevant. Bad newsletters with good incentives attract bad addresses that aren’t likely to engage with your emails.

Give people a reason to sign up beyond any incentives for becoming a new subscriber and give them absolute clarity about what they are signing up for.

Making Sense of Email Bounce Rates

Source: Really Good Emails

Use confirmed opt-in

Confirmed opt-in can help assure data quality across all of your subscribe forms. By ensuring that people must activate their subscription with a confirmation email, any erroneous or inactive addresses simply won’t make it onto your active subscriber list.

This can greatly reduce potential bounces, and lists using confirmed opt-in tend to be more engaged and active too.

Don’t use a free domain send-from address

Using a free domain email address such as Gmail or Hotmail can mean that your emails will fail a DMARC check by receiving domains operating a DMARC policy. Your emails will automatically bounce at Gmail and Yahoo, and are likely to be bounced or be routed to junk by many receiving domains.

Be sure to use a send-from address at your business domain and authenticate it. This will help ensure your emails are not caught in spam filters unnecessarily. Not only will you improve your bounce rates, but your general email deliverability will be improved.

Send consistently and frequently

Regular, consistent contact with your subscribers is an integral part of a successful email marketing program. Lists can go stale in as little as 6 months, and lists that have remained dormant over a longer period of time can see issues with engagement and spam complaints, as well as with bounces.

Send your recipients a welcome email to engage them from the start, and send them regular, relevant communications.

People often change their email addresses or leave previous ones abandoned, which are subsequently likely to bounce.

By contacting them regularly, you can be sure any bounces happen in low numbers over time, rather than seeing a large number of bounces at once from a list that is only contacted sporadically.

There is no universal solution to email sending frequency, but, if you only email your subscribers a couple of times a year, you should probably connect more regularly with your subscribers so they expect to hear from you on a regular basis and engage when they do.

Use a preference center

Be sure to include a preference center link in your emails so that encourage people to update their email address.

This can have a positive effect on preventing future bounces, and giving people control over the emails they receive is great for engagement and for cultivating trust.

Use a list verification service

If your list has been dormant for a period of time or if you have been sending via a system with less-than-stellar bounce management systems, you may want to use a third party list verification service to identify and remove undeliverable addresses ahead of sending.

You can use our App Store to integrate with services such as BriteVerify or Kickbox and verify your list.

Removing the undeliverable addresses is a must, but you may also see some services classify some addresses as risky or unknown. In those cases, removing them entirely may not be the right step, though we would highly recommend staggering sends to those kinds of addresses.

Add a small number of those risky or unknown addresses to your list to begin with, monitor the results, and then add some more if all goes well. If you see high bounce rates from these addresses, you may want to rethink using them at all.

Preventing a huge spike in bounce rates by proceeding carefully with riskier data is essential for good email deliverability. Inbox providers and spam filters pay close attention to bounce rates and attempts to deliver mail to invalid addresses.

If your bounce rates are sufficiently high, they may take steps to reject or block your emails entirely, and you could see bounces at legitimate inboxes too.

By verifying your list and adding any risky or unknown data steadily, you will prevent undue damage to your sending reputation and help the delivery of your emails with all inbox providers.

Be vigilant and monitor your results

As with engagement and other deliverability issues, the longer you leave bounce issues to fester, the greater the damage to your sending reputation. Monitor the results of your campaigns and journeys closely. If you see a spike in bounce rates, take a look at the bounce activity report.

Are you seeing an influx of hard bounces, or have you see a huge upswing in soft bounces, perhaps at a particular domain?

Take action to improve your signup form and double check your data sources and the age of your lists. Ensure your authentication is in place and that your send-from address is from the same domain.

If you’re still at a loss over why you are seeing high bounce rates, reach out to our support team, who will be able to help diagnose and resolve any issues.

Authenticate your emails

Email authentication is now one of the most important factors in a strong email marketing strategy. Failing to authenticate your sending domain means that receiving servers are likely to bounce or junk your emails, as they cannot determine the legitimacy of your sends.

By authenticating your sending domain, you are proving the legitimacy and authenticity of your emails to receiving ISPs, and this alone can have a profound effect on reducing soft bounces and improving the deliverability of your email campaigns in general.

Ramp up

In the event that you have a large email list that has not been sent to for some time, you’ll want to ramp up your sends carefully and monitor the results of your smaller campaigns ahead of sending to the full list.

Sending to the entirety of an older list and seeing a large number of bounces can be a disaster for the deliverability of your future emails. By sending to a smaller segment of your list first, you can monitor the performance and take steps to improve those results. By ramping up to send to your full list steadily, you can better control the impact of your campaigns, course-correct, if necessary, and preserve your sending reputation.

Wrap up

The key to understanding email bounce rates is to acknowledge that a small number of bounces are always to be expected, but preventing a large amount of bounces is often in your control.

High bounce rates are usually an indicator of issues with the age, permissions, or previous maintenance of your email list. By following the above steps and taking ownership of how your list is created and maintained, you can prevent high bounce rates and see further success with your email campaigns.

Post originally published Feb 22, 2017