Aside from 'cannot establish a two-way connection with the printer', the 'power on' button of my HP D2560 printer doesn't seem to get a steady light at all. It is always blinking for about 1 and/or to 45 blinks and suddenly turns itself off. So in the solution:
-I have to plug it
-wait for the first power button blink
-press the power button several times (sometimes long press, others long press and maybe double press?? IDK
-and when the blink is over I have to unplug it again and repeat the whole thing over again.
This happened when HP Update required me to restart the PC.
Imagine having to that just to get the printer it ready...what a waste in the time when you can do so much in doing that...