Can't ping second LAN interface on NSa3650
I have a LAN zone on X20 with ip 10.0.50.1 connected to switch1 with IP 10.0.50.2 vlan 50. I have set up a second LAN zone on X18 with ip 192.168.0.18 going to the same switch with IP 192.168.0.17 vlan 900. Firewall and switch1 can ping both interfaces.
I have a second switch connected to switch1 that can ping 10.0.50.1 but when I try and ping 192.168.0.18 the firewall drops the packet with a 'DROPPED, Drop Code: 501(IP Spoof check failed recorded in module network)' error.
What am I missing?