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Email bounces

An email that doesn’t reach its intended recipient, is said to “bounce” off the receiving email server. There are three major types of bounces: syntax bounces, hard bounces and soft bounces. This blog post aims to explain these types of email errors, and it will tell you how MailChimp and Copernica handle bounces.


Syntax bounces
This means the recipient’s email address was entered incorrectly. For instance:, or If the typo is as obvious as in these examples, you can easily correct the mistake and you’ll probably be good next time around.


Hard bounces
A hard bounce occurs when your email comes straight back from the receiving server with a message saying there is NO way in email land that it’ll ever get delivered at the email address that you intended. The main reason for this is the fact that the aforementioned email address doesn’t exist (anymore). Another reason might be the fact that the “from:” address, or even the sending email server, has been blacklisted by the receiving server.


Old mailing lists usually suffer from lots of hard bounces, which is one of many reasons why you should never ever use a purchased list of email addresses.


Soft bounces
Soft bounces are a different story. There are many hypothetical reasons why an email may bounce softly. One of these is the inbox of your recipient being full of other people’s crap. Another one might be that the receiving email server has temporary technical issues or that it (thinks it) has detected some kind of threath in the incoming message.


Whatever the reason, the message will be returned to sender. Depending on the sending email server, a second or third attempt will be made. If your message doesn’t go through in any of the attempts (there is a limit, but it varies), it’s end of story. Better luck next time.


MailChimp’s bounce policy
First of all, MailChimp will always tell you which email addresses resulted in bounces, and whether it was a syntax bounce, a hard bounce or a soft bounce. If available, you will also be able to view the receiving email server’s response message. This may help identify and solve any issues you might be experiencing.


Secondly, MailChimp automatically deletes email addresses that result in hard bounces. No rebounds here.


The matter of dealing with soft bounces is somewhat less straightforward. A soft bounce today might not be a bounce at all tomorrow. Therefore, MailChimp takes note of soft bounces, but it doesn’t delete the email address right away. MailChimp will simply try to send your next campaign to the same address, and it’ll keep trying until a total of eight attempts have been made. So if an email address keeps rejecting your messages, it’ll bounce itself right off of your mailing list.


For more information on bounces and how MailChimp deals with them, check this out.


Copernica’s bounce policy

Copernica allows you to set your own bounce handling rules. It will track all incoming errors (so you can investigate if you want to), but it will not automatically remove any email addresses from your database. Rest assured though: making Copernica handle bounces automatically is a walk in the park.


Here are some related articles from Copernica’s blog:


Bounce management

Process bounces automatically

Soft and hard bounces (Dutch only!)

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