Run a thick sheet of cardboard paper through a few times to clear any stuck debris. Clean any sensors and the rubber roller. Check your print settings to make sure they are correct. Primarily page size.
I hate to sound so generic, but check all of these:
Check the paper
Make sure the paper is the correct size and type for your printer. Remove any paper that is wrinkled, torn, or bent.
Check the paper tray
Make sure the paper is loaded correctly and the paper stack is even. Check for obstructions that might be preventing the paper from engaging with the rollers.
Check the printer settings
Make sure the paper size and type settings match the paper you're using. If you're using an optional paper cassette, make sure it's enabled in your printer's software.
Check the paper output
If paper is falling from the output tray, you can extend the paper stopper. If paper is falling from the paper tray, you can extend the paper stopper or put a box under it to prevent it from touching the floor.
Check for jams
If you think there's a paper jam, you can open the printer cover, locate the jam, and remove the paper.
Check for debris
Make sure there's no debris left in the printer.