Microsoft Outlook Email Error Code – 421 RP-003

In this post, let’s have a look at the error code “421 RP-003” that you get as bounce back when you are trying to send a email via Microsoft’s

Every Mail Servers that uses SMTP protocol to send emails have a list of errors that is usually displayed to the user when there is an email bounceback. Here’s we look at a specific error code that we receive and what it means for the user when using outlook ot Hotmail.

Error Message

421 RP-003

Error Details

The mail server IP connecting to server has exceeded the connection limit allowed. Reason for limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.