In this post, let’s have a look at the error message “5.0.350 – Generic error, x-dg-ref header is too long, or Requested action not taken: policy violation detected (AS345)” that you get when working with Microsoft 365 Exchange Online.
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.
Error Message
5.0.350 – Generic error, x-dg-ref header is too long, or Requested action not taken: policy violation detected (AS345)
Error Details
5.0.350 is a generic catch-all error code for a wide variety of non-specific errors from the recipient’s email organization. The specific x-dg-ref header is too long message is related to Rich Text formatted messages. The specific Requested action not taken: policy violation detected (AS345) message is related to nested attachments.
For more information, see Fix email delivery issues for error code 550 5.0.350 in Exchange Online.
