Connection error in qt5 network - c++

Question

i want to make a program like msn messenger , i have use qt5 with network , when i open a new connection with my local server , it doesn't work , it gave back to me that my server not connected i don't know the reason
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QtNetwork/QTcpServer>
#include <QtNetwork/QTcpSocket>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
void on_pushButton_clicked();
void newConnection ();
private:
Ui::MainWindow *ui;
QTcpServer *server;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
server = new QTcpServer(this);
connect(server , SIGNAL(newConnection()) , this , SLOT(newConnection()));
if(server->listen(QHostAddress::Any , 5050))
{
ui->label->setText("Not Start");
}
else
{
ui->label->setText("Server Started Now");
}
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::newConnection()
{
QTcpSocket *socket = server->nextPendingConnection();
socket->write("Hello Islam");
socket->flush();
socket->waitForBytesWritten(3000);
socket->close();
}
void MainWindow::on_pushButton_clicked()
{
newConnection();
}
this for call library
#-------------------------------------------------
#
# Project created by QtCreator 2013-11-03T10:00:37
#
#-------------------------------------------------
QT += core gui network
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = TCPTEST
TEMPLATE = app
SOURCES += main.cpp\
mainwindow.cpp
HEADERS += mainwindow.h
FORMS += mainwindow.ui
i tried to call new connection in mainwindow constructor but it didn't work

Answer 1

i think the error was in
if(server->listen(QHostAddress::Any , 1234))
which it worked but it must be
if(!server->listen(QHostAddress::Any , 1234))
to get server started