I have a client that is running Exchange 2010. Recently, several users have ported to Outlook 2010, and we have started getting several security errors about certificates. Most of these I have been able to bypass by installing the certificates from the server on the local workstations, but there is one error that eludes me. I am getting the error that "the name on the security certificate is invalid or does not match the name of the site." When I view the certificate, it is for an AD domain that used to be on the other side of our site-to-site VPN, but that no longer exists. If I try installing the certificate, it appears to succeed, but the next time I open Outlook, the same security error reappears. Does anyone have any possible fixes?