I get an error message when I try and print legal size documents. It had been working fine until a few days ago when I started getting this error message. I have only had the printer since July. I have Windows 7 operating system. It had printed these same documents a few minutes before I started getting the error message. The message tells me it is a paper size mismatch.
Try this link and it should help you resolve this issue- also using any other paper than "HP" branded paper can cause these as well.... also performing a "power reset may solve the problem- just pull the power cord from the rear of your printer with the printer turned on then unplugging it from the wall, waiting 20 seconds, then plug both back in and let printer come back on.
Although I work for HP, I am speaking for myself and not for HP. Kudos! If you feel my post has helped you please click the White Kudos! Star just below my name : ) If you feel my answer has fixed your problem please click 'Mark As Solution' and make it easier for others to find help quickly : )