Error 628 on Start Before Logon

Hey all,

Attempting to utilize the Start Before Logon feature of the VPN. I can get all the way up to the "Connecting..." message on the lock screen and then am presented with Error 628. Happens with Both 6.2.6 EMS-managed client and VPN-only client.

As soon as I log on to the machine as a domain user, I am able to log on to the VPN without issue, but never from the lock screen.

Ideas?