7 Most Common Reasons for an Increase in Bounce Rates

Rejection is a part of life. And if you pay very close attention, it can also be a big part of your success. If you’ve ever tried to pick up a lady, you know exactly what I’m talking about. Getting a successful response from the opposite sex comes with its share of lessons learned. As you think back to approaching that 6th grade crush that ended in harsh rejection, you learned to dress better, buy a comb and stop using pickup lines you found on the web.  I know what you’re thinking, the answer is yes I’m over her, my shrink said so. Whatever the case, the point is simple… rejection holds an important value in achieving success.

From the technically savvy to the creative marketers, we come across people that are not well-acquainted with the value of bounces, or email rejections, and what they mean. Bounce logs should be influencing change and a positive direction for your email program. In our latest Email Intelligence Report, inbox placement rates are still at all time low across the globe. Email bounces data can be another data point marketers can use for deliverability intelligence, and can inform marketers about deliverability issues, mailbox provider issues, or about potential issues.

Below you’ll find the 7 most common reasons for an increase in bounce rates and what it says about your program.

1. New lists cause new problems

Sending to invalid mailboxes is a common reason senders see an increase in email bounces, more specifically hard bounces. It’s quite common to see these, but a significant spike should prompt further investigation. Common causes can include a new list, a new client, or sending to an “old” list that has not been mailed to in a long time. At this point the damage is already done, but don’t miss out on the opportunity to prevent it from happening again as this is an important metric mailbox providers use to grade your reputation. Revisit your vetting process for lists and clients and ensure the sources of your email addresses are appropriate

2. IP blocks based on spamminess

Mailbox providers can increase your bounce rate by blocking your IPs altogether based on reputational metrics. High subscriber complaints is a common reason for mailbox providers to implement these types of blocks. Follow guidelines on their postmaster site to get these blocks removed, but be sure to do your homework in collecting all necessary information and making the right changes beforehand.

3. Sending to a list you weren’t supposed to

Whether intentional or unintentional, I’ve come across senders that have sent to a list that they weren’t supposed to. Causes for this can be a technical failure or that one… last… chance… to make a sale or get a member engaged. If suppression was due to a complaint or an unsubscribe, don’t be tempted to send it again! Eliminate the possibility of these technical failures, and educate the necessary staff on the damage this can create. You will see increases in bounces relating to invalid email addresses and reputation, among other issues.

4. Getting blacklisted

It’s common for mailbox providers to use third-party blacklists to help filter email. These can usually be found in the error code or might take a bit more digging into the postmaster site to see this. Bounces can also provide a link to apply for delisting. Find out as much as you can on why you may have been blacklisted by visiting sites for the mailbox provider and the blacklist itself. If you don’t identify the cause and make changes, you leave yourself vulnerable to be listed again.

5. Mailing past your own timer

By sending deferrals, mailbox providers can slow down your mailing for various reasons and cause messages to bounce out from your queue. When this happens, a lot of factors come into play. What are your retry settings? How long can mail sit in your queue until it times out? There are fairly standard recommendations for these settings but it also depends on how time sensitive your mailings are. A coupon offer good for the next 12 hours shouldn’t land in a member’s inbox the next day. So when a mailbox provider slows down your mail, it runs the risk of timing out because of your own settings, potentially leading to a high number of messages bouncing out. Revisit your MTA settings and monitor reputation so you don’t have to worry about deferrals to begin with.

6. Mailbox Providers on the move

As much as senders would love for mailbox providers to keep their thresholds consistent, forever and ever, they can’t. Mailbox Providers need to adapt because of the attacks they see from spammers all across the world. This means that thresholds for bounces and blocks can vary. Button up practices to adapt to these changes as they come. If you’ve done all you can, open a ticket and notify the mailbox provider for the chance of convincing them of a false positive…cross your fingers

7. Mailbox Provider oopsies

Nobody’s perfect. Mailbox providers sometimes have unplanned technical failures, it happens. Problems with their DNS record, MX record or returning an incorrect bounce code. I would say that this should probably be the last place you look to for an answer but it is a possibility. A great place to start when you think this has happened is to reach out to other senders and colleagues. Finding more senders with the same problem is a much stronger way to present a case to a mailbox provider.