Re: SD-WAN Can't use Ip pool
You have to assign the IP Pool to the interface with these CLI commands:
config firewall ippool
edit "IPPool name"
set associated-interface wan1
But, you have to force the trafic to the right interface in SD-WAN rules. In the current version, we can't assign IPPool on one interface and use outgoing IP address on the other. Feature Request have been asked for this.
If you want to use SD-WAN with IPPool, you have assign IP Pool on both wan interfaces, and don't forget to associate IPPool with the right one! :-)
Issue you currently have is weird: Fortigate tries to NAT on interface WAN2 with the IP Pool of the WAN1!
Let me know if it fixes your issue!
Philippe Gagné, NSE7