QSerialPort not Working on Windows

QSerial port in Qt 6 is not able to actually open a port.

The serialport/cenumerator example program lists one or more ports, e.g. "COM3". But if I attempt to open the port I get the error "The system cannot find the file specified".
e.g.

    QSerialPort port = QSerialPort("COM3");
    out << port.open(QIODeviceBase::ReadWrite);
    out << port.errorString();

With the serialport/terminal example program it lists COM3 as available but fails in the same way if I try to connect to the port.

It works on the Linux platform.