Seeing no one helps me, maybe a picture will be clearer.
That's what I have:
I opened port 26656 in TCP and UDP, and I did the same with 9999 but I do not understand why I have this message.
So I see my part (with the second computer) but I can not join the game with it, and I see NAT "no", I think the problem comes from there, but I do not know how the adjust. If a charitable soul could help me, it will be very nice because I dry there.