How to rely each LAN to a specific WAN

Hi everyone,

First of all sorry for my bad English,

I have 2 LAN on my FortiGate 51E v6.03 : one on a hardware switch on port LAN 1 and a second on a other hardware switch.

WAN 1 : ISP 1 Fiber

WAN 2 : ISP 2 LTE

I want that LAN 1 use only WAN 1 and  LAN 2 only WAN 2.

I have one VPN per LAN.

I have some policy who allow lan to join the dedicated WAN but when the two WAN are up, both client in LAN 1 and LAN 2 doesn't have internet access.

I tried these policy :

https://forum.fortinet.com/tm.aspx?m=157824

https://forum.fortinet.com/tm.aspx?m=127289

but still don't work with the two wan,

I can take screenshot of the policy if it can help.

I will force all the traffic from LAN 1 to pass through WAN 1 , idem for LAN 2 and WAN 2.

best regard