Click on finetune then on the left pane go to :  Live Access > All Discovered Devices > Unknown SNMP SysObjectID.

Copy the SysObjectID that you seen on the device, and search for device info in any public search engine.

You can also try to login into the device using its management IP and then check device inventory details to get device model.

Now go back to "Unknown SNMP SysObjectID" on the "FineTune" page. In the right pane it will show all the list of devices.

Now hover the mouse and click on drop down arrow and click on "Add to Vendor Model Table" and then enter the necessary details such as Vendor, Model, Driver etc then click on ok. Now try to discover again.