[solved] Multiplayer issue: peers can't connect (kick)

Hi.

I've been working on a game with a chat lobby. It works for me when the chat is started from my computer on localhost or even on my online website, but my friends who try to connect are kicked by the server when connecting to the chat room.

So I uploaded the multiplayer chat example included in Construct 2 and asked them to connect to it : http://canapin.com/construct/tutochat/

The only thing I changed is the game name. I can connect from localhost or this very address from my computer, but I asked three friends to connect to http://canapin.com/construct/tutochat/ and they are kicked automatically as well.

Edit : If I start /tutochat/ as the host they can't join, but if they start it as the host themselves, I can connect to them.

I'm puzzled. Any idea where do this issue could come from? Could it be a port issue?

Edit : solved, I had to put my local ip in the dmz in the router configuration.