Exchange 2013 SP1 On-prem - Disable Outlook Anonymous NTLM?

I'm aware there is a Group Policy admin template available to force Outlook to request only NTLM or basic authentication, however, I'd like to disable Outlook Anonymous NTLM on the server side in our Exchange 2013 SP1 on-premises installation.

Is there a method to disable Anonymous NTLM for Outlook client connections for the cas or organization?  I've tried the "Set-OutlookAnywhere" InternalClientAuthenticationMethod and ExternalClientAuthentcationMethod but Outlook is still able to connect with Anonymous Authentication selected for the logon network security.

Thanks

John Lowery