HP Photosmart A310 Compact Photo Printer - Manual (Page 63)

"Printing cancelled" or "Unable to communicate
with printer."
Cause The printer may have lost power or been
turned off, or the USB cable connecting the printer
to a PictBridge device or to a computer may have
come loose.
Solution Make sure that the printer is turned on
and that the camera USB cable is firmly connected
to the PictBridge port on the top of the printer. You
might need to resend your print job.
Troubleshooting 59