Cisco VPN Concentrator 3000 reject client authetication

Hi guys

I upgrade my primary domain controller from windows 2000 server to windows 2003 enterprise server. Now when users try to connect to the VPN from their homes, the request is rejected. I went into the concentrator and when I do a test to the nre DC(new dc has the same ip address that the old had) I get the following error:

 An error has occurred while attempting to perform the operation.

Authentication Rejected: Unspecified

Do I need to check any particular settings on the new DC? I can ping the DC from the concentrator.

Please can you give me some ideas
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What kind of authentication are you using?
Radius, kerberos, LDAP, NTdomain?
goodwill1Author Commented:
Im using kerberos authentication
Check this:

Known Issues when you use Kerberos between a VPN 3000 Concentrator and a Windows Active Directory (AD) Server

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goodwill1Author Commented:
Hi Geergon

I tried to install the hotfix but my service pack already have it so that did not work. Then I tried first changing on the user properties, under the account tab, where says Do not required Kerberos Preauthentication, I cheked that box ans then save it.

I went back to the concentrator and I test the user account and was successful.
I did not chenged the regustry key.

Thanks for your help
goodwill1Author Commented:
The info he gave me was right.
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