XADM: Change in Delivery Restrictions Does Not Update Immediately

This article was previously published under Q176648

If you send a message to a distribution list (DL) that is configured to reject messages from you, you will receive a Non-Delivery Receipt (NDR). If the DL is modified so that it does not reject messages from you, and you immediately try to resend the message, you may still receive an NDR. This is because the DL information is being cached by the message transfer agent (MTA). It takes 60 seconds for the change to be detected by the MTA. Therefore, if you wait 60 seconds before trying to send the message again, you will not receive an NDR.