Not sure if this applies to you but comport mismatch often means that the hardware is set/assigned a comport but the software is looking for it on another port. Often cables may have a USB connection but internally they convert to a standard serial connector. A quick way to see what your comport is set to is to open up the device manager in your computer then plug in your USB connection....You should see it appear under the USB heading....right click on it and review the properties....note the port assigned. Now fire up your software and look for something like config/settings/options You should see the comport listed....it must be set to match what you saw earlier in device manager. If not edit your settings to make them match.