Problem with DCOM connections after Windows Server updates from June 2021

Schardt, Wolfgang 1 Reputation point
2021-07-21T10:36:37.673+00:00

Hi.
After the last Windows Server updates/security patches we noticed that we have now a lot of communication problems.
We use DCOM communication to connect from a Windows application to a OPC DA server on another device.
After the last updates we can make the connection but after 8-10 miunutes this connection is interupted and we see this entry in the eventviewer:

DCOM got error "2147942405" from the computer xxx.xxx.xxx.xxx when attempting to activate the server:
{393AFF3D-96BA-4097-8388-A331E6C03103}

and also this one:
DCOM was unable to communicate with the computer xxx.xxx.xxx.xxx using any of the configured protocols; requested by PID 1c50

From OPC communication I can also see this messages:
116690-image.png

I have checked the internet to find out any reason why this happens now and how to solve it but without success.
If I uninstall the new Microsoft patches from the server it will work correctly again.

Has anybody seen the same isssue or can help me to solve it?

Regards,
Wolfgang

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  1. Jenny Yan-MSFT 9,326 Reputation points
    2021-07-23T02:27:06.527+00:00

    Hi,
    Noticed that you might have contacted MS phone support but still would like to share some of my findings:

    Have you verified the DCOM class of 393AFF3D-96BA-4097-8388-A331E6C03103?

    In threads of similar error codes below, it seemed the error massage recorded because of the incorrect permission assigned to user groups or to the dedicated registry key value.

    Reference links:
    https://social.technet.microsoft.com/Forums/windows/en-US/8bb5807f-73ba-4092-abc8-283d8fced6c4/request-a-certificate-from-certificate-service-fails-dcom-error-2147942405?forum=winserversecurity

    https://social.technet.microsoft.com/Forums/Windows/en-US/1d8431fc-2beb-4f89-8d72-16ba69a17032/dcom-got-error-quot2147942405quot-from-the-computer-xxx-when-attempting-to-activate-the-server?forum=winservergen

    If the Answer is helpful, please click Accept Answer and upvote it.

    Thanks,
    Jenny

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  2. Ray Garcia 1 Reputation point
    2021-09-23T15:18:41.83+00:00

    DCOM was unable to communicate with the computer computer using any of the configured protocols; requested by PID 729c (C:\Program Files\Microsoft Configuration Manager\bin\x64\smsexec.exe).

    I am still getting these errors on my DP , If I remove the patch it works well.

    Did this thread have somewhat if a "resolution" to these errors after the Patch? I was thinking it was something that MS fixed as far as security, that broke RPC Traffic.

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