I'm running LCS 2005 on Windwow 2003 SP2. I have a user that is unable to logon. In my Security log, I'm seeing Event ID 680.
Logon attempt by: MICROSOFT_AUTHENTICATION_PACKAGE_V1_0
Logon account: xxxxxxxxx
Source Workstation: xxxxxxxxx
Error Code: 0xC0000064
The client receives the error "Cannot sign in to Communications Service. You may have entered your sign-in name, username, or password incorrectly, or the authentication service may be incompatible with this version of the program..."