HP LaserJet 4050 Printer series - Manual (Page 115)

EN
Chapter 4: Problem Solving 93
3 Before replacing the tray, make sure
the paper is flat in the tray at all four
corners and below the tabs on the
guides.
4 Open and close the top cover to clear
the paper jam message.
If a paper jam message persists, there
is still paper in the printer. Look for
paper in another location (page 90).