We recently purchased a couple of the new Draytek 2927 Series routers and have set up SSL VPN with Active Directory authentication.
Although the mobile (Android/iPhone) apps work fine the Windows app immediately comes back with Can't connect to SSL VPN Tunnel server !!!

Also tried connecting with a local remote dial in account (to take AD out of the equation).
If we switch the protocol to PPTP then it connects and authenticates with both the local user or an AD account.

I am guessing that the current version of Drayteks Smart VPN Client for Windows (5.4.0) doesn't work with the Draytek 2927 Series SSL VPN.

I have logged a ticket for this but haven't had a reply so wanted to see if anyone else has had this issue as I have started deploying these and VPN is essential at the moment.

I doubt it's specific to the 2927 as it uses a near identical code base for the VPN as the 2926.