graphs are ok,but no data for custom data source

Hello everyone,

I am trying to using cacti 0.8.7g to graph my device--a firewall. All other
graphs are ok, for example, interface traffic by using generic snmp-enabled
host.

I found some other OIDs from the vendor, such as sessions, and want to
graph this in my cacti web.

By using snmpwalk command in the linux server of my cacti, I successful got
the correct number of sessions.

But when I put this graphic in cacti web, nothing display. I got the
graphic, but the number is data.

I had using cacti to get snmp data from some other devices with custom
graphic, it works fine. And I compared two of these data templates, graph
templates, both are same(of courese data source are different.).

So, I want to know how to debug this issue?

BTW, the number of my session is always 17xxxx, should I using other data
input method instead of Get SNMP data?

Thanks a lot!

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