Make sure the USB cable is completely plugged into both the Arduino board and the PC.
You may have a damaged/defective or charge-only USB cable. Try a different cable.
Either of the above can result in the power connections being made (and thus LED lights on the board), but no data connections (and thus no port for the board).
Hey in0
You just saved my day, actually my hole week. I have tried 5-6 different cables, and I was sure it was data cables - with all 5 connections. Now I have tried 3 more cables, and - bingo. The last one worked.
Not only is my IDE working. My Cloud IOT is working too :-)))))))))))