HP LaserJet Enterprise 600 Printer M603 series - Manual (Page 207)

3. Use the green handle to lift the paper-access
plate. Slowly pull the jammed paper out of the
product. Do not tear the paper. If paper is
difficult to remove, try clearing it from the tray
area.
4. Open Tray 1 and remove the envelope
accessory cover. If paper is present, remove it.
5. Rotate the paper guide to check for additional
jammed paper underneath. If jammed paper is
present, remove it.
6. Replace the envelope accessory cover and
close Tray 1.
ENWW Clear jams 191