Once in a while, when using the built-in VPN client in Windows 10, we would be able to begin to connect and actually authenticate, but not complete the connection. We would have an error similar to the following in the Application Event Log:
Even rebooting alone wouldn't fix the issue. But, the fix for us was easy. We only needed to delete and have windows recreate some items in the Device Manager. Try the following:
- Open Windows Device Manager
- Navigate to Network adapters
- Uninstall all of the WAN Miniport (XXXX) devices
- Or at least the one related to your VPN connection
- Right-click on any item and choose to Scan for hardware changes
- The WAN Miniport adapters should have re-created themselves.
- Try connecting to your VPN again.
That seems to clear out the necessary bit of whatever the VPN service was hung up on.