iOS 10 IPSec VPN

I am not having any luck getting my iPhone 6 using current iOS 10.3 to connect to a simple IPsec VPN on the Fortigate 60E using the iOS Native Dialup template. I have tried firmware 5.4 and 5.6 (5.6.1 too) and it never connects. I can get l2tp connections from macOS or Windows 10 as well as IPsec using Cisco VPN on macOS no problems. I have even reset the Fortigate back to factory defaults, removed all VPNs and still nothing.

Can anyone confirm this actually works?