server->setMaxPendingConnections(2);

void Widget::OnClientConnected()
{
    players++;
    QMessageBox::information(this,"connection!","client connected!");
    switch(players)
    {
    case 1:
        socket1 = server->nextPendingConnection();
        connect(socket1, SIGNAL(readyRead()), this, SLOT(OnReceiveData()));
        connect(socket1, SIGNAL(disconnected()), this, SLOT(OnClientDisconnected()));
        this->listWidget->addItem(socket1->peerAddress().toString()+":"+QString::number(socket1->peerPort()) );
        break;
    case 2:
        socket2 = server->nextPendingConnection();
        connect(socket2, SIGNAL(readyRead()), this, SLOT(OnReceiveData()));
        connect(socket2, SIGNAL(disconnected()), this, SLOT(OnClientDisconnected()));
        this->listWidget->addItem(socket2->peerAddress().toString()+":"+QString::number(socket2->peerPort()) );
        break;
    default:
//        server->nextPendingConnection()->abort(); // с этим вроде работает, но прочему maxPendingConnection не ограничивает не пойму
        players--;
        QMessageBox::information(this,"disconection!","client disconected because already 2 players!");
    }

}