I use IPTV Smarters Pro app on my Amazon Fire TV. It is absolutely an amazing app!!! Perfect Player app as well as others is crap compared to this app!
Do you mean Smarters ( not Smartens ) ?. This an App which comes in the form "Smarters" and Smarters Pro". I thing most people use "Smarters Pro"
I do and it is certainly working.
You of course need either a Playlist ( a .m3u file containing links to Streams ) or a Provider's details ( a URL, a Username and a PW ) to enter into the App for it to work.