Several functions of the Fortinet Firewall use a Radius Server.  I decided on FreeRadius.   It is installed in Ubuntu 24.04.   The Wifi 6 configuration uses it to assign users.   IPSec VPNs use Radius server groups.   

/etc/freeradius/3.0

clients.conf

This is added in the clients.conf.   ipaddr is the Fortinet 61F address that communicates with the Radius Server.  secret is the < Your long secret word that IPSec uses >

client my_wifi_ap {
ipaddr = xxx.xxx.xxx.xxx
secret = < Your long secret word that IPSec uses >
shortname = Forti61F
require_message_authenticator = no
}

Users: I use these users to connect to Wifi 6, IPSec VPN, SSL VPN

user_name Cleartext-Password := "password"

Radius Server on 61F