HTTP Error 403.7 - The client certificate was missing or unrecognized

Message :

The page you are attempting to access requires your browser to have a Secure Sockets Layer (SSL) client certificate that the Web server recognizes.

Cause :

Solution :

You MUST close your browser before any other authentication attempt to force a new SSL connection.

If the browser prompted for a certificate and the dialog has not been cancelled that means that a certificate has been sent to the webserver.
If the dialog is not shown at all, that means that Windows didn't recognize the certificate you wanted to use.

To make appear the dialog :

To add the smart card certificate to the dialog :

To check that the smart card certificate is trusted by the webserver :

More information :

http://support.microsoft.com/kb/186812