Lexmark M1140+
The printer dsiplays a 121.xx Service Fuser Error (except for 121.02. 121.16, 121.41 and 126.01 service errors, please follow troubleshooting steps in this article.
Make sure that the printer is plugged directly into a wall outlet.
Power off the printer, wait for a few seconds and power the printer back on.
LEGACY ID: SO7255
Troubleshooting 111.xx Printhead Errors on the Lexmark MS/MX 31x, 41x, 51x, and 61x
"42" or "42.xx" Toner Cartridge Mismatch Error