I had this exact problem recently with my printer. I tried everything listed in this forum but I could not clear the paper jam error. There was definitely no paper visible anywhere inside printer. Finally, I decided to try turning the printer over upside down, lay it on its side and putting on its back and then tapping it. The important part of this turned out to be laying it on its back, which means orienting the printer so that the front of the printer where the paper comes out is pointing straight up.
After setting the printer back down again I looked down into the paper feed where the paper goes in. Something blue that looked like the corner of a credit card had appeared. It had been hiding under the roller mechanism but now it was visible. Apparently, laying the printer on its back and tapping it had moved the object to where I could see it. I reached down into the paper feed with a pair of long nosed pliers and grabbed the corner of the object and pulled it out. It turned out to be an old ski lift ticket from when I had gone skiing. Apparently somehow it had gotten dropped down into the paper feed. Then it got under the roller mechanism and it was hiding under there.
In short, if you have this problem try reorienting the printer and try tapping it to see if anything drops out or becomes visible, especially down in the paper feed. It's easy for something like a business card, a credit card, a coin or a paper clip to fall down into there and jam up the printer.
