It is usually obvious, but sometimes you will get this error just as you turn on the printer. Check for a piece of paper in the fuser when this happens. Another time you get this error is when the paper fails to get picked up out of the paper tray. The printer goes through the action, but the paper pick up roller slips and no paper enters the paper path. You may be able to fix this temporarily by cleaning the roller with alcohol.
Rollers wear from use and they also age from ozone and heat.
A good work around is to reduce the file sent to the printer, if it is a picture, use less color. If it is a spread sheet, define less area to the print page. You could also drop the resolution. If this error occurs a lot consider adding more memory to your laser printer. Usually the correct paper type is not in one of the paper trays.