What causes HP printers to go offline?

1.

Reboot your printer by shutting it off and turning it back on again. Give the unit a minute or two to finish booting.

2. Verify that the printer is plugged in to your computer (for local printers) or that it has network connectivity. If the printer is a networked unit, double-check the link light on the back of the printer to make sure it’s flashing green.