Hi Carlos

I assume you are polling an SNMPv3 device? Before the actual polling starts, DataMiner needs to do a discovery to obtain the EngineID, EngineBoots, EngineTime. It will send a packet where these values are not filled in. In that way, the device will know it's a discovery. In Wireshark, this looks like this:

In the response coming from the device, these values will be filled in

The future communication will be based on those values.
Next to that, in that response, there will also be 1 variable binding present

That OID "1.3.6.1.6.3.15.1.1.4.0" is a special one meaning "usmStatsUnknownEngineIDs", because the the EngineID from the request was indeed unknown. As a side note: there are several others of those special OIDs

• 1.3.6.1.6.3.15.1.1.1 (usmStatsUnsupportedSecLevels)
• 1.3.6.1.6.3.15.1.1.2 (usmStatsNotInTimeWindows)
• 1.3.6.1.6.3.15.1.1.3 (usmStatsUnknownUserNames)
• 1.3.6.1.6.3.15.1.1.4 (usmStatsUnknownEngineIDs)
• 1.3.6.1.6.3.15.1.1.5 (usmStatsWrongDigests)
• 1.3.6.1.6.3.15.1.1.6 (usmStatsDecryptionErrors)

The above was just to give you some background about the discovery process. I would suggest to check the SLSNMPManager.txt logging for more details. If there would be nothing useful in there, I would suggest to start a Wireshark capture. This should be able to give you the exact reason why the discovery fails.

Hope this helps you further.