550 no such user - does not send NDR?
Question asked by mark - 5/12/2016 at 4:34 AM
We recently upgraded to SM14 and have encountered a bit of an issue - we have a user who forgot to set outbound authentication in Outlook.  On SM10 this used to generate a "greylisted" warning message so at least the user knew there was a problem, however on SM14 there isn't a non delivery report or any other warning.  So the user thought all their emails had been sent, but the email was never delivered.
The SMTP logs show the following (sender and recipients email addresses removed)
[2016.05.12] 11:43:54 [][9593079] rsp: 220 mail3.nsnetwork.net Thu, 12 May 2016 10:43:54 +0000 UTC
[2016.05.12] 11:43:54 [][9593079] connected at 12/05/2016 11:43:54
[2016.05.12] 11:43:54 [][9593079] cmd: EHLO CSDN04WS10
[2016.05.12] 11:43:54 [][9593079] rsp: 250-mail3.nsnetwork.net Hello []250-SIZE 26214400250-AUTH LOGIN CRAM-MD5250-STARTTLS250-8BITMIME250 OK
[2016.05.12] 11:43:54 [][9593079] cmd: MAIL FROM: <senders address>
[2016.05.12] 11:43:59 [][9593079] rsp: 250 OK <senders address> Sender ok
[2016.05.12] 11:43:59 [][9593079] cmd: RCPT TO: <recipients address>
[2016.05.12] 11:43:59 [][9593079] rsp: 550 <recipients address> No such user here
[2016.05.12] 11:44:02 [][9593079] cmd: QUIT
[2016.05.12] 11:44:02 [][9593079] rsp: 221 Service closing transmission channel
[2016.05.12] 11:44:02 [][9593079] disconnected at 12/05/2016 11:44:02
The Delivery logs show nothing and no NDR was generated. 
Have I missed a setting somewhere to generate the NDR?  I need some sort of notification back to users who try to send emails without authentication enabled, otherwise we'll get loads of support requests for missing emails!
Any help, comments or advice would be much appreciated.

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