When your HP printer keeps saying out of paper, the possible instances can be that:
1. It is truly out of paper hence the tray is empty.
2. Or, the tray is overloaded.
3. The paper tray is not properly set inside the printer.
4. The paper settings of the printer do not match the quantity loaded in the paper tray.
5. The paper-feed rubber is not clean or dusty.
If none works, contact a technical expert or you can also connect with us.