Which protocol should I use for Mac?
The protocols you can use for Mac depend on the version of the operating system.
Starting with macOS Sierra, it’s possible to use all available protocols. Older versions will have to use either PPTP or L2TP. We recommend switching to one of these two protocols when there are problems with your connection.
You can also install GOOSE VPN with the IKEv2 protocol on El Captain, you can download the manual at the download page. See the following link.
To access the page you will need an active subscription.