There can be several reasons for this type of error. This problem is related to the computer configuration and the serial ports installed. One of the following has happened: • There is no port available in the computer. Check Windows Device Manager for port configuration. • There is no port available in the computer. Check Windows Device Manager for port configuration. Keep in mind that ports are opened through Windows. It is not necessary to set or configure the baud rate, parity, stop bits, or flow control; WinMasterCG handles these items.