Hi ,
Once after verified above article if you still have the same issue please follow below steps.
Step 1
Check the communication between switch and the netsight server
if the device is not reachable you can find below logs from netsight server
Critical
Device Down x.x.x.x SNMP Contact Lost: No SNMP reply from device x.x.x.x. caused by SNMP Error: Timeout[4098], last uptime was 2 Days 15:57:07.0 1 10/23/2015 08:47:57 PM 10/23/2015 08:47:57 PM M13:U31-X450a-CE6
Step 2
Please remove the previous SNMPv3 configuration and reconfigure as per below article
https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-set-up-SNMPv3-on-EXOS
Step 3
If other switches are working fine with Netsight , please check the SNMP profile which is configured for not working switch.
If both profile are same then we have to check the credentials given for authentication (authentication and Privacy)
Step 4
Once after the configuration what is the SNMP status from switch -show management
SNMP stats: InPkts 9617 OutPkts 9617 Errors 36 AuthErrors 6
Gets 5422 GetNexts 4189 Sets 6 Drops 0
SNMP traps: Sent 0 AuthTraps Enabled
check the out put of
show log match snmp
Let me know if this works
Thanks,
Suresh.B