pfsense: all interfaces up, but all non default gateways down

I have almost the same issue on pfsense ver 2.3.2-RELEASE-p1 After hours of googling I found this. https://forum.pfsense.org/index.php?topic=105644.0

Sometime gateways do not want to response to ping. If your gateway's working but dashboard still shows that it's offline you can try changing the advanced settings on the gateway for Data Payload. (Define data payload to send on ICMP packets to gateway monitor IP.)