ASK - Open discussion - Internet not available for some host

hello there,

we use FG-60D, and one of ports connected to wifi router. dhcp on wifi router has been disabled, and from fortigate connect to port LAN on wifi router.

setting on fortigate for this port: dhcp server on, nat = enable, dns use same setting on fortigate.

here the questions. we have configured internet connection, but found :

some connected devices to wifi router can connect internet, and some can't.

any possibility that can cause this problem?

thank you