I forget which board I had the problem with but, I had to put a delay() in setup to give the serial monitor a chance to come up before the board tried to communicate.
In my case, I think I was printing from the board early in the sketch.
I forget which board I had the problem with but, I had to put a delay() in setup to give the serial monitor a chance to come up before the board tried to communicate.
In my case, I think I was printing from the board early in the sketch.