If you're getting ECU Not Found or Incompatible Device the problem isn't with the serial port. It's communicating with the PC but not with the ECU. Mine does the same thing but I don't know why. I need to change COM ports at random to get it to connect. I have 5 USB ports on my laptop that are numbered COM 3 through 7 when Windoze recognizes the USB adapter. They all have worked at some point, and all decide not to work at random so I have to switch once in a while.
As long as you're not getting a COM port error when you try to connect, you can try changing up the sequence of events when you try to connect. It's very random but it works for me. For example, if you plugged in the USB adapter, than launched CCOM, then turned on the key and that doesn't work, do those things in a different order. I've found that leaving the USB plugged in and CCOM open and just turning the key off then back on allows it to connect. I don't know if the problem is the CCOM software or Windoze but I have a helluva time connecting once in a while.
Good luck.
Jim