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Partner Insights: When to Remove Hard and Soft Bounces from Your File

Nov 19, 2020   |   5 min read

Knowledge Center  ❯   Blog

This month we asked several email industry experts to provide their tips and advice on a topic that is sure to be top of mind with the increased email marketing activity this holiday season: what to do about hard and soft bounces.

Without further ado, let’s introduce this month’s panelists:

Michael Thompson, VP, e-Services – ClickSquared, Inc.

Sundeep Kapur, VP, Strategic Marketing – NCR Corporation, eCommerce Solutions

Andrew Kordek, Chief Strategist and Co-Founder –Trendline Interactive

FP (FreshPerspectives): What’s the best rule of thumb to use for determining when to remove hard and soft bounces from your file?

Michael: Bounce management is a key component to building and maintaining a good sender reputation, thereby ensuring high deliverability and inbox placement. In essence, a bounce is a message the receiving mail server sends back to inform you that your email failed to be delivered to the intended recipient. The reason could be a permanent failure where the address is no longer valid (e.g. “Unknown User”) or a temporary failure where the address is still valid but was not delivered for another reason (e.g. “Mailbox Full” or “Blocked for Spam”).

ClickSquared considers permanent failures as hard bounces and temporary failures as soft bounces. Hard bounces should be removed from your file upon the first incidence – sending to unknown users is a key factor ISPs use to determine your reputation.

When to remove soft bounces from your file is less straightforward and should be based on the frequency that you send and your ability to react to bounce conditions. The majority of soft bounces we see these days are due to blocking issues – resolving these issues will eliminate the block and allow delivery. So the goal is to walk a fine line between not being too aggressive such that good records are removed from your file or too lax so as to keep records that will never be delivered. As a rule of thumb for soft bounces, we recommend a setting that allows for 6 consecutive soft bounces before removing the record from your file.

FP: Sundeep, what’s your take on this?

Sundeep: There are three “first” things I look at every morning with my email campaigns. I start by looking at my unsubscribes, as this tells me if I “ticked off” my consumers. The second statistic I look at is my opens, as this gives me an indication of how responsive my consumers were to my campaigns. The third number I look at are my bounces.

Bounces matter to my email-marketing program, as they are a direct contributor to my “score” or “reputation” amongst the ISPs. I treat these bounces with kid gloves, as bounces to ISPs are as credit scores are to lenders.

The two key bounce metrics to watch are hard versus soft. Hard bounces come back with a 5XX code, and I take these off immediately. Soft bounces come back with a 4XX code and, depending on the specific code, I might re-target these email addresses 3-10 times before removing them from my list.

For example, a soft bounce attributed to a DNS failure leads me to investigate why the DNS address is failing. A soft bounce due to a mailbox being full serves as a Catch-22. Why keep trying a mailbox that is already flooded? Wait a bit, and send them your next message when they are most likely to pay attention to your message. I call my soft bounces “dribbles,” as we try our best to recover them.

My advice is to direct your bounces to a customer service help desk and have them research the true cause of the bounce. Also, update your consumer information database with a bounce for that email ID. That way, when that specific consumer contacts your brand, you can report the “bounce” to them. By doing this, your help desk is given an opportunity to reinforce the importance of your emails and remind your subscribers of the value these communications offer.

Excessive bounces will affect your deliverability. Take an extra step and train your front lines on the importance of collecting the correct email ID. Share the numbers with your team; it will go a long way in improving your email marketing program.

FP: Andrew, do you operate under a general set of rules on bounce management, or do you take it case by case?

Andrew: There is no general rule of thumb in determining when to remove hard and soft bounces from your file. It is situational from company to company. Aggressive organizations would look to remove hard bounces after 3-5 re-tries, while more conservative ones would look to remove hard bounces after one bounce.

To me, it’s all about how you run your email program and how often things like this are tracked over time. I tend to err on the conservative side due to all of the new engagement rules at the ISPs. It’s wise to follow the “one hard bounce and you’re out” rule on Tier 1 ISPs, while you might want to try a second time with the Tier 2 ISPs.

In regard to soft bounces, I have always found the rule of “3 consecutive soft bounces over a 15 day period” to be a winner. Lastly, it’s always a good idea to be conservative initially and then dial it up if you feel you might be “losing” too many potential subscribers. If you start out too aggressive, it might (and I emphasize “might”) come back to bite you in the butt if your reputation and deliverability get affected. Digging yourself out of a hole is much harder than digging a little deeper every so often.

FP: Sender reputation is an increasingly pressing concern for email marketers. Pay close attention to your hard and soft bounces, and take heed of the advice shared here by our esteemed partners.

A word to the wise: Before removing any records from your file, be sure you’ve tried every avenue to reconnect with those seemingly “lost” customers. You can bank on 30% of your file changing their email address in any given year due to changes in employment, school, ISP, etc. Before giving them up for lost, try to recover those valuable contacts with an Email Change of Address (ECOA) service. Consider quarterly ECOA updates to keep your bounce rate as low as possible. As our partners cautioned, a high bounce rate can have a deleterious effect on your deliverability, so take the necessary precautions.

Mike, Sundeep, and Andrew, many thanks for your great tips, and have a joyous holiday season!

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