Connecting Qt to SQlite

I'm trying to use Qt to connect to a SQlite database as a login window. However when I click the login button it just loops connecting to the server and doesn't send any infomation to it.

My code to connect to the server when the program runs is:

    public:
        QSqlDatabase mydb;
        void connClose()
        {
            mydb.close();
            mydb.removeDatabase(QSqlDatabase::defaultConnection);
        }

        bool connOpen()
        {
        mydb=QSqlDatabase::addDatabase("QSQLITE");
        mydb.setDatabaseName("C:/Users/Jack/Desktop/Project/SQlite/dataset.db.sqlite");

        if(!mydb.open()){
           qDebug()<<("Status: Disconnected");
           return false;
        }
        else{
            qDebug()<<("Status: Connected");
            return true;
        }

My code to then attempt to login to the server is:

connOpen();
    QSqlQuery loginqry;
    loginqry.prepare("select * from login where username='"+username+"' and password='"+password+"'");

    if(loginqry.exec()){
        int count;
        count == 0;
        while(loginqry.next()){
            count++;
        }
        if(count==1){
            ui->Statuslabel->setText("Login successful");
            connClose();
            this->hide();
            behindlogin behindlogin;
            behindlogin.setModal(true);
            behindlogin.exec();
        }
        if(count>1)
            ui->Statuslabel->setText("Duplicate usernames and passwords found!");
        if(count<1)
            ui->Statuslabel->setText("Login unsuccessful");

The error that Qt gives is:

QSqlDatabasePrivate::removeDatabase: connection 'qt_sql_default_connection' is still in use, all queries will cease to work. QSqlDatabasePrivate::addDatabase: duplicate connection name 'qt_sql_default_connection', old connection removed. Status: Connected