certificate revocation check fails
When using remote desktop on windows 7, and remoting into a server 2008 R2 machine, I get the message " certificate revocation check cannot be performed " The certificate is installed correctly, and works for windows 2003 servers, I've checked the security settins on the server, but can't find anything wrong, remoting in from windows xp machines work fine. How does certificate revocation check work, and do I need to allow access to a particular website through our firewall? If this is the case, what is the URL, and what ports does it need for revocation checks to work. The failure only occurs from within our organisation, and we access the internet through an isa server proxy, with a 10 min session timeout. remoting into the server from outside the organisation from a windows 7 macine works fine, so I can only assume it's something to do with internet access.
Has anyone any ideas?