Thanks for the response. Yes it looks like switch is dropping all the packets and they are unable to reach the collector, so yes collector is not receiving any traffic at all. Here you can see the 'udp packets drop' value keeps on increase after each polling interval.

http://prntscr.com/azsy75

FTOS version : http://prntscr.com/azsz3z

Oh sorry for misunderstanding. I am attaching output here.

Thanks for help Daniel. Could you please let me know if there's some 'redirect output to file' supported in switch? As the #show tech contains really long output which looks difficult to copy / paste on external media.

>> Along with info on what port the collector is plugged into?

Actually, we've total of two switches SW1 and SW2. Some of the servers are connected behind SW1 and some of behind SW2. In our case, we're exporting sflow data of SW2 and the collector is physically connected behind SW1 but both agent / collector are able to ping each other. Should this work ? Or we must connect collector to SW2 to fetch sflow data ?

Thanks for great suggestion.

Sorry for late response! Still everything is in dropped state. Should i move collector to same switch then ? 

I've configured collector on same switch but error still persists. :-(