Error message when you sign in to an Office Communicator Web Access (CWA) Web site: "Cannot sign in because your computer clock is not set correctly or your account is invalid. (Error code: 0-1-492)"

When you sign in to an Office Communicator Web Access (CWA) Web site (such as https://im.contoso.com) that is hosted on a Windows Server 2008, you may receive the following error message: Be aware that the computer name and CWA Web site alias are different.

This issue occurs because the Service Principal Name (SPN) of the CWA alias is missing.

To resolve this issue, add a Kerberos SPN to the CWAService account that matches the CWA Web site alias, such as https://im.contoso.com. Then, restart the server.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.