Try commenting it out and see if it works, the code looks like it disconnects anyone trying to connect so yeah.
(Comment it out like this:Code:/*for (int j = 0; j < Server.getPlayerManager().players.length; j++) { if (j == playerId) continue; if (Server.getPlayerManager().players[j] != null) { if (Server.getPlayerManager().players[j].playerName.equalsIgnoreCase(playerName)) disconnected = true; } }*/