Cisco Unity Connection

Unity Connection Receives NDRs to the Unaddressed Distribution List

Document ID: 116398

Updated: Aug 14, 2013

Contributed by Scott Hills, Cisco TAC Engineer.



This document describes the process to troubleshoot when Non-delivery Receipts (NDRs) are reported to the recipient in Unity Connection.


Occasionally, you might see unexplained NDRs reported to the receipent in Unity Connection. When it is reported, the NDR reports to the Unaddress Distribution List. There might or might not be reports of messages that were not reported to Unity Connection users. Other settings might include:

  • Single Inbox is also configured.
  • Unity Connection is configured to relay the message to Smart Host if Unity Connection cannot deliver the message.
  • Unity System Settings > General Configuration > 'When a recipient can not be found' is set to 'Relay message to Smarthost'.

Solution 1

In order to troubleshoot this issue, perform these steps:

  1. Navigate to Cisco Unity Connection Serviceability.
  2. Choose Trace > Micro Trace.
  3. Choose Message Transfer Agent (MTA) 10 - 30.
  4. Choose Simple Mail Transfer Protocol (SMTP) 10 - 30.
  5. Attempt to reproduce the issue or note the exact time of the next NDR received.
  6. Use the Real-Time Monitoring Tool (RTMT) to collect files and collect Connection Message Transfer Agent and Connection SMTP Server from 15 minutes before and after the NDR is received.

Solution 2

In the Connection MTA trace you might see:

07:31:59.878 |28321,,,MTA,12,Thread=MtaMailDelivery-7; 
class=CsUnityMtaMessage;Attempting to relay a message that had already been
relayed. NDRing the message to:f99b2b0c-7f8d-440e-838d-c4214a8bcc8c

When this occurs, navigate to Connection Administration > System Settings > SMTP Configuration > Smart Host.

You might find that the Smart Host is the actual Unity Connection server name or IP address. This
causes a loop which is related to the message found in the MTA trace. Change this setting to an Exchange server.

Updated: Aug 14, 2013
Document ID: 116398