why am i getting this qsqldatabase errors

Question

I am having trouble while working with qsqldatabase. Here is my main code

 QSqlDatabase db = QSqlDatabase::addDatabase("QPSQL");
    db.setHostName("acidalia");
    db.setDatabaseName("customdb");
    db.setUserName("mojito");
    db.setPassword("J0a1m8");
    bool ok = db.open();
    if(ok)
        qDebug() << "Successful";
    else
        qDebug() << "Unseccussful";

Here are my errors