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No AD connection on server

I have a Windows Server 2008 that have some problems.

When I try to add a member to a group (Remote Desktop Users) I get this dialog when clicking "Advanced" telling me "The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you. "
I tried to remove the machine from DNS to see if it reregistered, but it didn't (after reboot).

On the server where I am trying to add a user to a group, I get this event:
The Security System detected an authentication error for the server
ldap/DC2.MyDOMAIN.dk. The failure code from authentication protocol 
Kerberos was "  (0x80080341)".

Open in new window

Level: Warning
IEvent ID: 40960

Any ideas?
Kasper Katzmann
Kasper Katzmann
1 Solution
Krzysztof PytkoActive Directory EngineerCommented:
Can you verify if you DC/server are activated (genuine) ?

Sushil SonawaneCommented:
Remove the member server form domain and rejoin then check
Sarang TinguriaSr EngineerCommented:
Have you checked the DNS setting on this server ..Is it pointing to internal DNS ..??

See below link if it help
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Kasper KatzmannAuthor Commented:
Problem solved. It turned out to be due to an old error/mistake in group policy, that only allowed the servers to use DES_CBC_MD5. After removing the bad GPO the policy wasn't reset on the server.

This is what I did to solve the problem:


Opened Secpol.msc


Went to Local Policies/Security Options


Found Network security: Configure encryption types allowed for Kerberos and removed the tick from DES_CBC_MD5 (and all others if there were any)
Thanks for your suggestions anyway. It could just as well have been any of that.

Case closed :-)
Sarang TinguriaSr EngineerCommented:
Thats Great
Kasper KatzmannAuthor Commented:
I found the solution on my own

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