I experienced this same exact issue but it was on the multiplayer that is built into factorio. Whoever hosted the game could play on the server but if someone tried to join to the game it wouldn't display "server not responding".

Factorio 0.16.51 2018-07-21 9_21_20 AM.png Whenever I try and join a multiplayer game. The game gets stuck downloading the game map and eventually, the server stops responding.
I have played multiplayer in the past so I'm unsure what the problem is. My friend also has this problem. my friend and I ...