HP LaserJet P4015 Printer series - Manual (Page 177)

4. Reinstall the envelope feeder.
5. Press OK to clear the jam message.
6. If a jam message persists, an envelope is still jammed in the product. Look for the jam in another
location. See
Jam locations on page 161 .
7. Replace the envelopes, making sure that you push the bottom envelopes in slightly further than
the top envelopes.
ENWW Jams 165