Last polled value of a performance monitor "No data available"

Last polled value of a performance monitor "No data available"

Hi, i am new using opmanager, i'm trying to monitor a few devices using SNMP. The problem is, when in the dashboard i add the last polled value of a performance monitor widget sometimes it displays the correct value, however most of the time shows "No data available".

I would appreciate if someone can help me.

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