How to Read Email Bounce Backs and Errors

Some bounce backs are very cryptic and full of codes and numbers. How are you supposed to figure it out? Let’s break down a typical bounce back:

Note 1 : The top part of this message is the actual bounce back. This is the “meat” of what you need to identify.  Sometimes bounces include lots of numbers and codes; ignore all that and find the string that references the 400 or 500 number.  In this case the error is ‘550 No such user’. Since this account doesn’t exist at the point of delivery the message was bounced by the recipient server.

Note 2 : The second half of the bounce is the email headers. Keep in mind that not all bounce backs include this information, however, most do. This information is really helpful as it contains the Sender, Recipient, Date, Time and Subject, as well as server hops. If you are unable to figure out the issue, make sure you send the complete bounce back including the email headers to your IT administrator.

All of this information is critical in understanding a bounce back.