Only connect if Proxy Server certificate has this principal name

This policy setting specifies the required certificate principal name for the RPC proxy server for Outlook Anywhere.

If you enable this policy setting, you must enter a server principal name. You must precede the server name with "msstd:" for this configuration to work. For example, you would enter the following text if the server principal name is mail.fourthcoffee.com:

msstd:mail.fourthcoffee.com

If you disable or do not configure this setting, Outlook uses the certificate principal name that is specified in Autodiscover.