SSTP VPN in Mac OS X Sierra

Since the update to Sierra i cannot connect to my server using a VPN SSTP Connection. I tried several tools such as EasySSTP and iSSTP.

Before the upgrade it worked fine but now it seems like Mac OS isn't even trying. He just waits and then timeouts. The strange thing is that my collegaue also upgraded to OS X Sierra and he can connect with the same VPN SSTP tool and settings.