Lexmark C912 User Reference Manual page 126

6
Close the duplex unit covers.
7
Push the duplex unit until it stops.
8
Close the access door.
9
Press .
Go
If the paper jam message continues, check and clear all paper from the paper path.
200 Paper Jam <x> Pages Jammed (Check Areas A-F, T1-5, MPF)
Clearing paper jams
121