Unable to monitor WatchGuard Firewalls using SNMP

[adasi]

I have been able to setup Zabbix agents on Servers, and it works really well. But when i setup SNMP on our Firewalls (Watchguard M Series), Zabbix server is not receiving any SNMP messages.
I am able to ping the firewall from the Zabbix server and vice versa.

Any ideas will be greatly appreciated.

Regards,