Ran into an issue today where trying to setup a Microsoft VPN client into a corporate Microsoft server. When I kept trying to get connected the VPN would fail with the error code of 806. For this specific customer they required the type of VPN to be PPTP.
I found the solution to my problem was on my Cisco ASA. All I needed to do was add inspection for PPTP traffic.
service-policy global_policy global
After adding the “inspect PPTP” on the firewall I was able to connect the VPN up with no issues. Hope this helps.
Jason Howe, PEI