Security warning when you start Outlook 2007 and then connect to a mailbox that is hosted on a server that is running Exchange Server 2007 or Exchange Server 2010: “The name of the security certificate is invalid or does not match the name of the site”
I ran into an issue where I had imported a SAN certificate into my exchange organization. Once I had imported it I started to get outlook SSL warnings. The issue was that the internal URLs for many of the services outlook connects to were setup with my internal server domain IE host.internaldomain.com. Now I was faced with an issue where I could not get another SAN cert to encompass the host names of my internal domain, because the Domain admin previous to me named the internal domain of a legitimate domain and we did not own that domain. ie internal domain is contoso.com or yahoo.com these domains are owned by someone else thus no SAN cert will be issued. The way around this was I changed the internal URL entries for multiple virtual directories, and created a DNS look-up zone. I found A KB article that shows how to do this.
http://support.microsoft.com/kb/940726