When KB2585542 is present and you cannot open fortigate web interface, add a registry key
HKLM\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL DWORDx32 SendExtraRecord Value: 2
If you can't establish a VPN connection after loging in, turn off your firewall. Open CMD.EXE in elevated mode and type:
Netsh advfirewall set allprofiles state off
to turn the firewall off and
Netsh advfirewall set allprofiles state on
to turn the firewall on.