The advice to push the green lever inside the paper tray compartment and clicked it back on worked as a charm for me. I was really frustrated because I just took this printer for a repair for the same thing and it cost me $100.0 dollars for repair, only to get home and the same thing reappears again.
I should have checked this site before spending $100.0 for nothing.
Thank you so much for those who provide free service for others to benefit from.
God bless you!