I've got no idea how I've done this, but somehow I have broken my PPTP in Windows 8.1
Using the identical settings on a Windows 7 Pro machine, I cannot connect my WIndows 8.1 Pro to a PPTP server, and I have tried three different servers we use. The WIndows 7 machine connects perfectly.
On Win 8.1 Pro, it almost looks like it is going to connect,
First I get "connecting to .."
Then "Verifying your Credentials.."
Then "Completing the Connection..."
and then it drops out with "Error 720. A Connection to the remote computer could not be established. You might need to change the network settings for this connection"
Up until this week, I've never had any problems with the VPN connection.
The only thing I can think that may have caused it was a Bluetooth driver update (I have an ASUS laptop and was annoyed about a btvstack error I was occasionally getting) and I also installed software for, but didn't configure a Fritz!VPN connection. I've since uninstalled both of these.
I've spent the last 12 hours trying to resolve this, at one stage having to restore my computer after following some rogue registry hack and TCP/IP reset I found on google. In the process I've learnt so much about starting Windows 8 in safe (next to damn near impossible)