There could be several reasons why your scanner is not feeding sheets into the unit.
1. The document feeder may not have been set up correctly. Check to make sure it is positioned correctly and that the paper guide is not blocking the path of the paper.
2. If you are using an automated document feeder (ADF), the paper tray may need to be refilled. Make sure there is enough paper to complete the scan job.
3. The scanner may not be properly connected. Check that all cables are plugged in correctly and that the power source is turned on.
4. Dust and debris inside the scanner can interfere with the scanning process. Make sure that you regularly clean the interior of the scanner with a soft, dry cloth.
5. Other programs running in the background may be conflicting with the scanner. Close out any other programs that are open before starting a scan job.
If none of these fixes resolves your issue, you may need to reset the scanner or contact the device manufacturer for further support.