Problem using QMessageBox from my own class

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C++

QT-Creator

I have a class I've created it works fine. I want to add the ability to display an error using QMessageBox. When I did this the code after the call to my class is not executed.

Here is the class

#include <connect2sql.h>


connect2SQL::connect2SQL(QObject *parent) :
QObject(parent)
{

    qDebug() << "inside constructor connect2SQL called from " ;
}


 connect2SQL::~connect2SQL()
{
    //qDebug() << "inside destructor connect2SQL::~connect2SQL";
}

 void connect2SQL::TryConnect()
 {

     db.setHostName(Server);
     db.setDatabaseName(Catalog);
     db.setUserName(User);
     db.setPassword(Password);
     //qDebug() << "inside connect2SQL::TryConnect db.open() =" <<db.open();
     if (db.open())
         isConnected = true;

     else
     {
          // this didn't work
         // apparently can't use
         // message box in your own class
//         QMessageBox::warning(
//                 NULL,
//                 "SQL connection failed",
//                 "SQL connection failed");


             loggedIn=false;
             TryAgain=true;
             Abort=false;
             isConnected = false;




       }


           //qDebug() << "inside  connect2SQL::TryConnect isConnected =" <<isConnected;



 }

Here is the code where I call the class

con->TryConnect();

    //qDebug() << "inside Login dialog:: isConnected =" << con->isConnected;


    if (con->isConnected==false) {


        if (QMessageBox::question(this, "Login Failed",
                                  "Login Failed Retry?", QMessageBox::Yes, QMessageBox::No) == QMessageBox::Yes)
        {
            loggedIn=false;
            TryAgain=true;
            Abort=false;


        }
....

Not all the code is here, the point is the QMessageBox::question doesn't appear and the program ends with exit with code 0. If I take the QMessageBox::warning out of my class then QMessageBox::question does appear. Any ideas?