When a mailbox provider rejects or defers an email it sends back a message explaining why. Those messages begin with a three digit number (starting with a “5” for rejections and a “4” for deferrals), followed by text that explains why the mail wasn’t accepted. That text often contains a link to follow for more information, or a mailbox provider specific code you can...
I’ve shared a version of this image repeatedly. I think it was only my Facebook friends that got the stick figure screaming in frustration, though. The reality is bounce handling is one of the most frustrating pieces of email delivery. Not only that, many people in the email space treat it as a simple process. It’s really not as simple as we’d like it to be. The above image was...
The question came up on slack this morning about bounce rate benchmarks. What are the normal / average bounces that different ESPs see? Does region matter? What’s acceptable for bounce rates? Bounce rate is an overall measure of address quality Here’s your the chance for ESPs share the data from your customers. We’re interested in anything you care to share. But more detail is...
A few hours ago I was reading an ESP blog post that recommended removing addresses after they were inactive for a year because the address could turn into a spamtrap. That is not how addresses turn into spamtraps and not why we want to remove active addresses. Moreover, it demonstrates a deep misunderstanding of spamtraps. Unfortunately, there are a lot of myths and misunderstandings of...
Bounces and bounce handling is one of those topics I’ve avoided writing about for a long time. Part of my avoidance is because there are decades of confusing terminology that hasn’t ever been really defined. Untangling that terminology is the first step to being able to talk sensibly about what to do. Instead of writing a giant long post, I can break it into smaller, more focused...
Over the past few years a number of email delivery products have been launched. Many of these products are intended to improve deliverability by improving metrics. The problem is they don’t work the way their purchasers thing. Take data hygiene services. For the most part, these services take a list of email addresses, do data analysis and magic and then return a “clean” list to...
A number of people have mentioned over the last couple weeks that they’re seeing a spike in Yahoo rejecting mail with
554 delivery error: dd Requested mail action aborted
Discussions on various mailing lists indicate these messages are related to inactive accounts. Addresses that bounce at Yahoo with these codes should be handled as inactive addresses and removed from future mailings.
It should be easy, right? Except it’s not. So why is it so hard? With one-on-one or one-to-few email it’s pretty simple. The rejections typically go back to a human who reads the text part of the rejection message and adapt and makes the decision about future messages. The software handles what to do with the undeliverable message based on the SMTP response code. In the case of a 5xy...
I’ve got multiple clients right now looking for insights about bounce handling. This means I’m doing a lot of thought work about bounces and what they mean and how they match up and how different ISPs manage delivery and how different ESPs manage delivery and how it all fits together. One thing I’ve been trying to do is contextualize bounces based on what the reason is. Despite...
A few years ago I wrote a series of blog posts about zombie email addresses. Zombie addresses are those that someone owned and used and interacted with, but for whatever reason stopped logging into and checking. This series started with the time before the zombies, and moved on to the zombie uprising. Then discussed how they don’t eat brains, but they do love to take a bite out of...
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