How to disable Non-Delivery Reports (NDR) in Microsoft Exchange server Author: Luis Fernandes July 11, 2020 13:18 AnswerTo enable and disable the NDR's through Microsoft Exchange server, please review the following Microsoft Knowledge Base articles below:Microsoft Exchange 2000/2003 http://support.microsoft.com/default.aspx?scid=kb;en-us;294757 Microsoft Exchange 2007/2010 http://technet.microsoft.com/en-us/library/aa998621(EXCHG.80).aspx Microsoft Exchange 2013/2016 http://technet.microsoft.com/en-us/library/jj649325(v=exchg.150).aspx Related articles How to prevent a Reverse NDR Attack How to stop NDR Spam? A user is compromised and receiving a lot of NDR messages Error: '550 5.7.1 Message Rejected as Spam by Content Filtering' in the Message Delivery Log Error: '550 5.1.1 User Unknown' in the Message Delivery Log