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critical HP
Error Code Priority input jam (door open, media out)
Signifies a paper jam or door being improperly closed on the priority feed tray area.
? What Causes This
Open tray or obstruction inside priority tray.
✓ How to Fix It
Check that the tray is secure and free of obstructions; follow steps in Clearing jams for detailed resolution.
Source: page 61 of the official manual
From the manual
This error code appears in:
HP Laserjet 1015 Printer