These are possible solutions. Try one or more of the following:
Make sure your computer is connected to the printer and is turned on.
Check the USB cable for any obvious damage.
Firmly plug the square end of the USB cable into the USB port on the back of the printer.
Firmly plug the rectangular end of the USB cable into the USB port of the computer.
The USB port is marked with the USB symbol.
If you are using an external print server, make sure it is connected. For more information, see the print server documentation.