No paper is loaded in tray 2 (optional) or paper is not loaded properly. Follow the procedure below to load paper properly.
Hold both sides of tray 2, lift it slightly, and pull it toward you.
Pull tray 2 completely out. Take care not to drop it.
Lift off the cover.
Squeeze the paper guide release, and then slide the paper guides into position according to the paper size.
If paper is already loaded, remove it from the paper tray, fan it well, and tap it on a flat surface such as a desk to even the edges. Check that the position of the paper guides and the front end guide match the paper size.
Load paper with the print side face down but not over the limit mark.
Re-attach the cover.
Hold both sides of tray 2, and push it gently in until it stops.