I would run the SNMPwalk.exe program in your Orion installation folder. Run Wireshark on the Orion server and capture the traffic. Is the SNMP reply even coming back? Any data in it? Any authentication or encryption failures (if SNMPv3)? Check logs of device you're trying to monitor and validate that the SNMP authentication and encryption were successful (if SNMPv3)
There are some examples here:
You could also SNMPwalk from the monitored device using the expected credentials. If it doesn't work locally, doing it over the network won't be possible either.
actually tried all. I also manually install agent. I also used some 3rd party tools but no reply via snmp or wmi. all I got is icmp reply (with agent and without agent both)