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Mark Wipf

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Exchange 2016 fails due to corrupted machine account

I have an Exchange 2016 CU22 server that has been working well when suddenly stopped flowing email.  I've had multiple eyes and experts review the server, rebuilt all the connector components, all to no avail.  Since the failure, the security log is filled with the below event:


An account failed to log on.

   Security ID:      NULL SID
   Account Name:      -
   Account Domain:      -
   Logon ID:      0x0

Logon Type:         3

Account For Which Logon Failed:
   Security ID:      NULL SID
   Account Name:      EXCHDAG$
   Account Domain:      SomeLocalDomain.LOCAL

Failure Information:
   Failure Reason:      The user has not been granted the requested logon type at this machine.
   Status:         0xC000015B
   Sub Status:      0x0

Process Information:
   Caller Process ID:   0x0
   Caller Process Name:   -

Network Information:
   Workstation Name:   -
   Source Network Address:   -
   Source Port:      -

Detailed Authentication Information:
   Logon Process:      Kerberos
   Authentication Package:   Kerberos
   Transited Services:   -
   Package Name (NTLM only):   -
   Key Length:      0

This event is generated when a logon request fails. It is generated on the computer where access was attempted.

The Subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe.

The Logon Type field indicates the kind of logon that was requested. The most common types are 2 (interactive) and 3 (network).

The Process Information fields indicate which account and process on the system requested the logon.

The Network Information fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases.

The authentication information fields provide detailed information about this specific logon request.
   - Transited services indicate which intermediate services have participated in this logon request.
   - Package name indicates which sub-protocol was used among the NTLM protocols.
   - Key length indicates the length of the generated session key. This will be 0 if no session key was requested.


I am convinced this is the core issue that needs to be resolved.  Any ideas on how to fix this Security Failure?  It seems like the SID has either been wiped out or there is some corruption in the AD machine account.  I have already done an Exchange recovery build and the issue persists.  I've built a new exchange server to migrate to but the migration fails due to this machine account problem.

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Peter Hutchison
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That's a great suggestion!  Can you direct me to the specific Security Policy I should add the machine account to?

An interesting fact the needs to be taken into account is that the issue survived through an Exchange recovery build.  That tells me the ultimate source of the missing rights is in Active Directory.  Where in Active Directory should an Exchange server machine account be added?

Adding the machine account to the Local Administrators group did not change anything.
@ste5an, As part of the initial troubleshooting, I did disable the security suite on the server (Carbon Black).  As stated in the original problem description, this is an Exchange 2016 server.  Also, this issue started Wednesday afternoon December 26th.  It should be also noted that it initially appeared like a backpressure flag was thrown for the system drive, which was 119GB in size and free space was at 18.8GB.
We're seeing this being mentioned by contractors:

That's tied to @ste5an's comment as well I think.

A third party sanitation and continuity service would allow for the local scan engine to be disabled as all baddies are taken care of before they get to the Exchange server(s).
And a little more detail here:

#Microsoft and #Exchange starting off 2022 with a User generated imageas of 00:00UTC with freezing transport of all emails flowing through it On-Prem due to failure converting the new date... User generated image. Solution is to disable the AntiMalware Scanning temporarily via Disable-Antimalwarescanning.ps1. 1/x

EDIT: Another:
@Philip, I have not seen this error in the event logs (yet) and my issue started many days before the 2022 role over.  I will disable the AntiMalware scanning as a preventative.
Got it. Thanks for the clarification.
The Exchange account should be member of the Exchange Servers group in the Microsoft Exchange Security Groups OU. See Disabling Antimalware service and restart MSExchange Transport service as well for the 2022 date bug.