Problem of the SD-WAN and static route

Hi, guys,

I am rather new to Fortigate and SD-WAN setup.

Few days ago, I created SD-WAN zones for some network lines, but, I deleted a SD-WAN zone by accident.

Later after I re-created that SD-WAN zone, I found these interfaces (already added into a SD-WAN zone) missed the default route, as the attached (the circled interfaces).

Event I modified the Fortigate configuration by CLI, these interfaces are still missing the default route.

Any recommendation to add back the default route to these interfaces (port 5, 6, 7, 8 ) ( except recreating the SD-WAN).

I am using Firmware 6.4.1 for Fortigate 400e.

Many thanks.