none
451.4.4.0 Primary target IP address responded with: "421.4.4.2 Connection dropped due to socketerror."

    问题

  • Mail lingers in the Exchange 2010 queue viewer.

    Error: 451.4.4.0 Primary target IP address responded with: "421.4.4.2 Connection dropped due to socketerror."

    -hotmail.nl

    -hotmail.com

    -live.nl

    -outlook.com.

    The other mailflow is still normal.

    This is going on since 7-7-2018 and the queue is running all over.

    Users get notified within the Outlook client: The delivery of your message to the following recipients or groups has been delayed:

    This message is not delivered yet. There is still trying to deliver the message.The server will try to deliver this message in the next 1, 19 and 59 minutes. You will receive a message if the message could not be delivered after that time.



    A tip to convert the False "StartTLS" setting of the connector to True did not help.

    Set-Send Connector -Identity <sendConnectorName> -IgnoreSTARTTLS $ true (MSExchangeTransport services restarted after the change)

    The problem is still present.



    Greets

    /\/\arcel
    2018年7月11日 20:41

全部回复

  • Hi,

    Based on your description, email sent to some of the email domains will get stuck in the queue, with the 421.4.4.2 Connection dropped due to socketerror.

    Did you configure a reverse lookup for your public MX record?
    Are you using the MX record or smart host to send outbound message?

    For troubleshooting:

    Please add the DNS forwarders for the above domains, then check the box "use the external dns lookup settings on the transport server" on the send connector Network settings and restart the MSExchangeTransport service.

    Hope it helps.

    Regards,

    Manu Meng


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    2018年7月12日 7:53
    版主
  • Thanks you for the reply.

    I believe it is not an DNS issue so far.

    We have already 2 DNS entries in th DNS forwarder settings of the DNS.

    We can resolve for example the hotmail env:

    ..


    It is also possible to the check the port 25 connection:

    ..

    Result:

    ..

    2018年7月13日 8:18
  • Thanks you for the reply.

    I believe it is not an DNS issue so far.

    We have already 2 DNS entries in th DNS forwarder settings of the DNS.

    We can resolve for example the hotmail env:

    ..


    It is also possible to the check the port 25 connection:

    ..

    Result:

    ..

    So did you go on to configure the send connector external dns lookup settings?

    Regards,

    Manu Meng


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    2018年7月13日 8:56
    版主
  • yes, we have check the "Use the External DNS lookup settings... " but no results.

    Error: 451.4.4.0 Primary target IP address responded with: "421.4.4.2 Connection dropped due to socketerror."

    the message:  451 4.7.500 Server Busy. Please try again later from [193.172.9.65] (AS3110)


    2018年7月13日 9:51