I have noticed that when my computer is left alone for a long period of time (overnight), the HHKB becomes inactive. I have to unplug the keyboard USB and upon replugging it, it works. I have tried my keyboard on a Macintosh and Chrome book, and the same thing happens. I have also tried turning on dip switch 6 (wake up mode), but that does not help (I still have to replug the USB in order to get it to work).
Any suggestions?