The paper feed rollers are likely dirty or have lost traction. You need to clean them.
- Turn off and unplug the printer. Disconnect all cables.
- Slide out the paper cassette and remove any paper.
- Carefully place the printer on its side. Watch your fingers.
- Use a soft, moist cloth to clean the cassette rollers inside the printer. Gently rotate them to clean all around.
- Return the printer to its upright position. Don't leave it on its side, as ink may leak.
- Reload paper, slide the cassette in, and reconnect power and cables.
If that didn't work, check for paper jams or torn pieces inside the feed path. Also ensure you're using supported paper that isn't too thick, curled, or glossy for the main tray.