Check the ADF cover to make sure it is not ajar on the left or right-hand side. Close it by pushing on both the left and the right-hand sides of the cover at the same time, or on its center.
The LED indicator will light up as if Ready even if the cover is not fully closed.
If the issue persists, check the paper for any damages or if it is in good condition. If damaged or in poor condition, replace the media or scan the media using the flatbed glass.
Make sure that the ADF supports the weight of the media being used. Use the flatbed when scanning heavier paper.
Check the media side guides; make sure they are snug but not tight.
Check the curl of the media. Try to flex, fan, and straighten the print media before loading to reduce the curl.
Make the stack of documents in the ADF tray smaller and stacked neatly.
Ensure that the media is not being shoved into the tray.
Update the printer firmware with the latest version.
Refer to “Updating the Lexmark printer firmware” for steps to update the printer firmware.