PyQT5 : Unable to Create Another Dialog While One is Open

[Axel_Erfurt]

your dialog does never end.

here is an example for an input Dialog

from PyQt5 import QtWidgets

class Login(QtWidgets.QDialog):
    def __init__(self, parent=None):
        super(Login, self).__init__(parent)
        self.textName = QtWidgets.QLineEdit(self)
        self.textPass = QtWidgets.QLineEdit(self)
        self.textPass.setEchoMode(QtWidgets.QLineEdit.Password)
        self.buttonLogin = QtWidgets.QPushButton('Login', self)
        self.buttonLogin.clicked.connect(self.handleLogin)

        self.buttonCancel = QtWidgets.QPushButton('Cancel', self)
        self.buttonCancel.clicked.connect(self.handleCancel)

        layout = QtWidgets.QVBoxLayout(self)
        layout.addWidget(self.textName)
        layout.addWidget(self.textPass)
        layout.addWidget(self.buttonLogin)
        layout.addWidget(self.buttonCancel)

    def handleCancel(self):
        self.close()

    def handleLogin(self):
        if (self.textName.text() == 'foo' and
            self.textPass.text() == 'bar'):
            self.accept()
        else:
            QtWidgets.QMessageBox.warning(
                self, 'Error', 'Bad user or password')

class Window(QtWidgets.QMainWindow):
    def __init__(self, parent=None):
        super(Window, self).__init__(parent)

    def msgbox(self, message):
        msg = QtWidgets.QMessageBox(1, "Information", message, QtWidgets.QMessageBox.Ok)
        msg.setStyleSheet("QLabel{min-width: 100px;}")
        msg.exec()

if __name__ == '__main__':

    import sys
    app = QtWidgets.QApplication(sys.argv)
    login = Login()

    if login.exec_() == QtWidgets.QDialog.Accepted:
        window = Window()
        window.show()
        window.msgbox("it works!")
        sys.exit(app.exec_())