The printer detected a media jam in the fuser area. The printer expected a page to come through the fuser but either the sensor has toggled or has stayed opened to long. If media is frequently jamming in the fuser area when duplexing 11x17 or A3 size, then check and clean the duplex roller. Open the lower left cover and check for any jammed media. On the left side of the fuser check the fuser exit sensor flag. Perform the sensor test in the Service Mode Menu. Replace the fuser.