After 2016 CU6 - SMTPClient: ReceiveResponse: 452 4.3.1 Insufficient system resources - from Domino server delivering to Exchange RRS feed

  • Question

  • Since installing Exchange 2016 CU6, messages are building up in the delivery queue on Domino Server. Domino receives email and forwards to Exchange.

    Exchange is telling Domino 452 4.3.1 Insufficient system resources

    Mail goes through to Exchange after a delay. up to 4hours later

    2 Exchange Servers in DAG, both on CU6. Upgraded one week apart with no issue after the first server upgrade

    Nothing stands out in the Exchange logs to indicate an issue such as Back Pressure.

    Plenty of disk space on all drives

    32GB RAM 82% used, <50% CPU

    Event ID 1006 started appearing after CU6 but from what i can tell this is unlikely to be related, but i'll mention it in case it helps

    Every 30 mins 1006 gets logged once for each mailbox database

    The performance counter '\\EXCHANGE1\MSExchange Assistants - Per Database(msexchangemailboxassistants-mailboxdb1)\Event Dispatchers Catching Up' sustained a value of '8,000.00', for the '30' minute(s) interval starting at '22/09/2017 12:22:00 AM'. Threshold breached since '19/09/2017 12:22 PM'. None Trigger Name:EventDispatchersCatchupQueueTrigger. Instance:msexchangemailboxassistants-test-mailbox

    the value doesn't change per mailboxdb. other posts mention this as a bug will will clear on restarting. other says it doesnt clear.

    Help appreciated to work out the issue if anyone has experienced this.

    Friday, September 22, 2017 2:20 AM

All replies

  • I found the problem and it was Back Pressure, but on the other member of the DAG.

    C: drive free space 3.3 GB

    Event ID 150006

    Microsoft Exchange Transport is rejecting message submissions because the available disk space has dropped below the configured threshold.The following resources are under pressure:
    Used disk space ("C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\data\Queue")
    Used disk space ("C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\data")

    Friday, September 22, 2017 2:54 AM
  • Hi,

    Thanks for contacting our forum.

    As the Event 15006 logged, please verify that the hard disk contains more free space than the threshold that has been configured for the Transport server. Please refer to:

    If in the case, you cannot make the necessary disk space adjustments. Then we can choose to change the location of the queue database to a disk drive with sufficient free space. It can be done by following the following steps:

    • Begin by terminating the transport service
    • Go to the original queue folder (the one containing all the queue database and logs) and copy the files to the new desired directory.
    • Open notepad and open the file C:\Program Files\Microsoft\Exchange Server\V15\Bin—EdgeTransport.exe.config
    • Edit the following Keys:

    <add key=”QueueDatabasePath” value=”C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\data\Queue” />

    <add key=”QueueDatabaseLoggingPath” value=”C:\Program Files\Microsoft\Exchange Server\V15\TransportRoles\data\Queue” />

    Note: The paths above need not be identical.

    Hope it helps.


    Jason Chao

    Please remember to mark the replies as answers if they help.
    If you have feedback for TechNet Subscriber Support, contact

    Monday, September 25, 2017 5:12 AM