Windows built in VPN, dont use as network credentials

I know this is an old question, but I believe there is a better answer in that it doesn’t require any server-side changes: edit the VPN settings to not use the VPN credentials when authenticating to network servers. This setting is not exposed through Windows’ UI, so you need to locate the .pbk file associated with your VPN connection (%AppData%\Roaming\Microsoft\Network\Connections\PBK\rasphone.pbk for user VPNs) or (%ProgramData%\Microsoft\Network\Connections\Pbk\rasphone.pbk for system VPNs).

Right click on the VPN’s .pbk file and open it with Notepad. (Remember to untick ‘Always use this program for this file type’)
Roughly 5 lines down will be an entry ‘UseRasCredentials=1’
Change this to ‘UseRasCredentials=0’
Save the file.
I sourced these instructions are from: https://social.technet.microsoft.com/Forums/windows/en-US/0204464d-e32d-4584-966b-60788cce0d6f/disable-creation-of-vpn-session-credential-in-credential-manager-without-disabling-all-of

https://serverfault.com/questions/322235/do-not-use-vpn-credentials-to-connect-to-network-resources