Why qDebug() returns "failed" when I try to connected the PostgreSql Database

Question

I am currently working with QT creator and PostgreSQL.

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include <QString>
#include <QDebug>
#include <QtSql>

static QSqlDatabase DB = QSqlDatabase::addDatabase("QPSQL");

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    DB.setHostName("db.fe.up.pt");
    DB.setDatabaseName("****");
    DB.setUserName("*****");
    DB.setPassword("****");



    if (DB.open())
    {
        qDebug() << "Connected!";
        QSqlQuery query2;
        if(query2.exec("SET search_path TO INFI")){
            qDebug() << "Schema OK";
        }
    }
    else
    {
        qDebug() << "Failed to connect.";
        //ui->LogOk->setText("You not are connected to VPN!! ");
    }
}

MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_orders_clicked()
{

   QSqlQuery query;
   QSqlQueryModel *model = new QSqlQueryModel;

   if(query.exec("SELECT * from INFI.orders")){
       qDebug()<< "TOP";
   }
   else{
       qDebug()<< "Failed";
   }
   model->setQuery(std::move(query));

}

I am trying to run this piece of code, and when I execute my app my connection with the DB are ok. But I dont know why I cant execute this query when I press the button, my qDebug always return me "failed", what I am doing wrong?? This is the tables and the schema I am working. I want to select all the items of my orders table, this table is inside INFI schema.