Is there a freely available online 7 piece Endgame tablebase? The only 7 piece site I heard about is http://tb7.chessok.com/ , and upon registration I am able to setup various positions with 2-6 pieces . However as soon as I setup a position with 7 piece, I get an error about service not being avaiable. Has anyone had better luck or know of any other site with 7 pieces tablebases?

Update: in the end I discovered that FinalGen solved a vast majority of positions I was interested in, included those with more than 7 pieces. http://finalgenchess.ovh/home_ing.php
Original Answer:

7-men Lomonosov is free as an Android application.



Update - September 2018:

7-men Syzygy is available for free. Also available from Lichess.