Dell B1260dn says No Paper, yet it has plenty of paper

Just started getting this message today on my B1260dn printer. I also tried a test page directly from the printer menu, and it also gave me the same error.

What are the steps for this printer to troubleshoot?

Is there a sensor, wheels, or rollers I need to clean?

Will the following advice given by a previous user work for this model?

1. turn off the printer.
2. remove the paper tray.
3. turn the printer on its back so you can see the bottom of the printer where the paper tray used to be.
4. You with see a black bit of plastic in a T shape with rubber tires on each side.
5. Those tires peel off. Peel them off and flip them inside out and re fit them and test...