Unmanaged Detector does not detect anything

Dear all,

I am trying to use Unmanaged Detector in some network subnet. In few network subnet, it's work. But in few another subnet it is not work. I tried to use many client but nothing changed (SEP 12.1.7 and SEP 14). Also, i can use advanced ip scanner to find out MAC and hostname of PC in the same network subnet. 

Please help me. Is there any requirement to use Unmanaged Detector.

Sincerely.