Maintainer of WebTorrent here: the problem is on how WebRTC works and its various settings. Using a good STUN servers with your own tracker server should be the best solution. Using TURN servers also helps peers connect, but then it's no longer real P2P. Current work is being dedicated to updating the code base to ES6 and soon to ES7, which will improve many things and force recent versions of Node/Browsers to be used. See https://github.com/webtorrent/bittorrent-tracker/issues/199