PyQt5 : Interpreter Crashes While Initializing Message Box

[iMuny]

did you not show the MainWindow() ?

if __name__ == '__main__':
    connectDB()
    app = QtWidgets.QApplication(sys.argv)
    MainApplication = MainWindow()
    MainApplication.show()  ## show main window
    app.exec()

Yeah i've set it to show through my setupUI method, the complete code is below ...

from PyQt5 import QtWidgets
import mysql.connector
import sys
from fuzzywuzzy import fuzz, process

class MainWindow(QtWidgets.QWidget):
    def __init__(self):
        super(MainWindow, self).__init__()

        self.client_name = QtWidgets.QLineEdit()
        self.check_button = QtWidgets.QPushButton("Add Client to BABAR AKRAM")
        self.check_button.clicked.connect(self.addName)

        self.setupUI()

    def setupUI(self):
        container = QtWidgets.QGridLayout()
        container.addWidget(QtWidgets.QLabel("Client Name"), 0, 0)
        container.addWidget(self.client_name, 0, 1)
        container.addWidget(self.check_button, 1, 0, 1, 2)
        self.setWindowTitle("For Updating Client List Manually")
        self.setLayout(container)
        self.show()

    def addName(self):
        print("Add button clicked")


def connectDB():
    try:
        connection = mysql.connector.connect(host='######', user='######', password='######')
        cursor = connection.cursor()
        cursor.execute('USE client_list;')
    except:
        msg = QtWidgets.QMessageBox(3, "Warning", "Please check the internet connection", QtWidgets.QMessageBox.Ok)
        msg.exec()


if __name__ == '__main__':
    connectDB()
    app = QtWidgets.QApplication(sys.argv)
    MainApplication = MainWindow()
    app.exec()