Not much of a Fortinet user, but helping a customer with transitioning from their old PPTP(yup) to something more secure. I've created a Windows security group called VPNUsers and I have a Windows 2019 DC that the firewall is communicating with - added the security group successfully. Using the current Forticlient build, a couple of users I've added to the VPNUsers group can VPN no problem. I then add a couple more users and I'm receiving 'Error: wrong credentials'. I verified that the creds are correct as I can login to workstations on the lan. What gives?