Make sure the Lexmark OCR scan software is installed on your laptop. The software is available only on the installation disc that came with your printer. If you still haven't installed the software on your computer and you don't have the installation disc, please contact Lexmark Technical Support Center to request for one.
If you were able to scan documents before using your Lexmark printer, it could be just a slight communication issue. A quick fix for most communication errors can be achieved by
resetting the printer and/or rebooting the PC. Simply disconnect the printer
from your computer (if USB connected)> reboot your pc > unplug and
re-plug the printer into the power source to reset it. When the printer turns
on, reconnect it to your computer (if USB connected). Then try to print again
once the computer fully recognizes the USB connection or when the WiFi light on
the printer turns solid green (if WiFi connected.).