Dears, my environment is Exchange 2007 with windows server 2003 & 3 domain controllers I have a warning on one of the mailbox servers (which I have 2 working in CCR) which has the following information Source: LASSRv Category : SPNEGO (Negotiator) Event ID :40960 Description The Security System detected an authentication error for the server ldap/dc02.mydomain.com/mydomain.com@MYDOMAIN.COM. The failure code from authentication protocol Kerberos was "The attempted logon is invalid. This is either due to a bad username or authentication information. (0xc000006d)". I search for it on internet but most of the result is when the domain controller showing this error I couldn't find any error realted to exchange Note: this error happens only to one of the mailboxes & the event is appearing to one of the domain controller only (DC02) Regards,

try this one http://support.microsoft.com/kb/224196Raj

Hi Ramos, Please check if the following KB can help you: http://support.microsoft.com/kb/824217 If the issue persists, since this is a Windows error, I suggest you write the post in our Windows Server forum: http://social.technet.microsoft.com/Forums/en/category/windowsserver/ Thanks, Elvis