HP LaserJet Pro 400 Printer M401 series - Manual (Page 115)

Clear jams from the output bin
CAUTION: Do not use sharp objects, such as tweezers or needle-nose pliers, to remove jams.
Damage caused by sharp objects will not be covered by the warranty.
1. With both hands, grasp the paper, and
carefully pull it free from the product.
Clear a jam in the duplexer area
1. Open the rear door.
ENWW Clear jams 103