Here's the link: http://iptvprivateserver.com/
I have Kodi installed on a FireTV. I went to pay and it asked for an optional MAC address, I gave the one from Settings on FireTV and it said that my MAC address was invalid.
Edit: http://ftazeta.com/kodi-xbmc/70820-kodi-iptv-stalker.html#post395331
The reason the MAC was invalid is because you set it up wrong. Set your MAC on IPTV Stalker as 00:1A:79:XX:XX:XX (Enter your last 3 sets of MAC digits where the XX's are). Then enter that MAC on the donation checker page. I'm using a FireTV and it works fine.
I've been using it without issue for weeks. I don't use it anymore on my FireTV though. I bought a dedicated box for it (Mag 254)
The box is fantastic. Highly recommend just getting a dedicated STB.
Developers probably blacklisted portable sticks so people have to buy more keys. I don't trust the company behind it using donations to make a profit. At anytime they could be shut down and your money is gone. I'll stick to the free streams. These guys seem shady.