Exact CN and other to use in server certificate when setting up VPN

I am following this link to set up a VPN server

https://www.techsupportpk.com/2017/01/set-up-vpn-server-on-windows-server-2016.html

It is generally excellent, but when I try to connect from the client it complains about the certificate name not matching. I think setting Certificate Properties could use a little more clarification. EXACTLY what properties should be added and EXACTLY what should they be.

Example

Local Domain: Contoso.local

Web Domain: Contoso.com

Internal Server FQDN: ContosoServer.Contoso.local

SPECIFIC QUESTION:

• Assuming the client comes in via externally Contoso.com, should the value specified be ContosoServer.Contoso.local or ContosoServer.Contoso.com ?

FYI I have tried both and both attempts the client would not connect and complained about the certificate name not matching or something like that.