A friend of mine hosts a server, actually for Arma 3, in one of his home PCs, he set it up for Argo LAN. All of his friends but me were able to join his server, I was the only one left out, with the message of the OP.
He tried to set it up PW broadcasting, again everybody but me was able to join it.
They say see my pawn name joining in, then leaving.
Really frustraiting.