Email Marketing – SMTP Error Codes

A good ESP will be registered to the feedback loops of all major email clients as well as maintain a good relationship with them in order to help resolve any deliverability problems that may be experiencing. However, if this is not a service your ESP provides and you maintain this yourself, or you just want to know more information about the kind of issues that your programme is experiencing (ask your ESP for the SMPT error codes they regularly see returning from your broadcasts) the following short list of links to error codes and descriptions might be useful to you.

• Yahoo - Descriptions of specific SMTP errors. - http://help.yahoo.com/l/us/yahoo/mail/postmaster/errors/;_ylt=AsaIk4YT7Y0WsxkTgOCE880IJHdG
• AOL – SMTP Error Messages - http://postmaster.aol.com/Postmaster.Errors.php
• Hotmail – SMTP Error Codes - http://mail.live.com/mail/troubleshooting.aspx (Scroll to bottom of page)
• This very helpful guide breaks the codes down and explains what each part of the number means on its own and the message it is giving you - http://email.about.com/cs/standards/a/smtp_error_code.htm

This information is a major step in identifying any problems surfacing in your email broadcasts such as sending too many emails too quickly or receiving a high number of complaints, so don’t forget to act on/urge your ESP to act on the information you are receiving back from these sources!