emails stuck in "undefined queue" after changing send connector on Exchange 2016 CU9 RRS feed

  • Question

  • Hi,
    Yesterday we changed a send connector on our Exchange 2016 servers. (Exchange 2016 CU9)
    > We added Exchange 2016 servers as source, and removed old 2013 servers from the connector.

    After the change we restarted both transport services.

    After some time we noticed that all emails were queueing up in the "undefined queue". (which included all emails sent/received)
    No emails got delivered in any direction.
    We had to restart all Ex2016 servers to resolve the issue.

    Does anyone know why this happened?
    I've never had any issues, and to what I know restarting the transport services used to be enough.
    Tuesday, August 28, 2018 7:25 AM

All replies

  • Hi,


    After restarting all Exchange 2016 servers, this issue has been resolved, right? Based on my experience, "undefined queue" may be related with submission process, so if this issue occorrs again, you can try to restart the Exchange mailbox transport submission service and check the result.


    Gavin Gao

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    Wednesday, August 29, 2018 6:00 AM
  • Thanks Gavin,
    I had to change another setting on a receive connector, and was able to simulate the issue again.
    I tried restarting the services mentioned above ,but the queue remained. 
    So I had to restart all servers again.
    Never had this issue before, so might be a bug?
    Wednesday, August 29, 2018 8:29 AM