Surf Soho and GRE tunnel

Hi, am I able to configure my Surf SOHO MK3 for VPN pass-through while allowing GRE protocol packets? I’m having no luck connecting to a Windows (2008) VPN server, with my desktop and Surf SOHO on the client side (using the native Windows 10 VPN client). I have opened all ports for the server IP, and tried all the VPN pass-through options.

Alternatively, can PepVPN use GRE 47 protocol as the client?