In this post, let’s have a look at the error message “
These are the errors that you usually receive when there is a problem in delivering the email message that was sent by you. These errors are generated and sent by Office 365. This is usually alled as DSN which stands for delivery status notification or in simple words bounce messages.
NDR or Non-delivery report is one of the common type of message that you receive which indicates to the user that the email was not delivered.
This value is assigned by the mail server that rejected the original message and indicates why the message was rejected. These codes are defined in RFC 3463, and use the format abc x.y.z, where the placeholder values are integers. For example, a 5.x.x code indicates a permanent error, and a 4.x.x code indicates a temporary error. Although the enhanced status code is often generated by an external mail server, Exchange Online uses the enhanced status code value to determine the text to display in the user information section.