Multiple IP address on ProxMox host

G'day.

I have searched for an answer, and not found it, so please excuse me if I am asking something that has been answered.

Set-up:

There are two physical NICs in the server. I have the following:
192.168.1.238 on vmbr1 which goes via eth1
192.168.2.238 on vmbr0 which goes via eth0
192.168.3.238 on vmbr2 which goes via eth0
eth0 is plugged into a switch with the other servers in the 192.168.2.0 and 192.168.3.0 servers.
eth1 is plugged into a switch with the 192.168.1.0 network machines.
192.168.1.0 ==> LAN
192.168.2.0 ==> DMZ
192.168.3.0 ==> DMZ

Problem:
I cannot ping the 192.168.3.238 from any network.
I cannot ping any 192.168.3.x address from the ProxMox host.

Additional info:
I can ping 192.168.1.x and 192.168.2.x from the ProxMox host.
I can ping 192.168.1.238 and 192.168.2.238 from the respective networks.
I can ping all the ProxMox host IP addresses from within the host itself, so I know they are configured and answering.

I have rebooted, a couple times, for various reasons.

I appreciate any suggestions.

Cheers.
Bobby