Lexmark MS810n / MS810dn / MS810dtn
Open the rear mailbox door.
Remove the jammed paper.
Note: Make sure that all paper fragments are removed.
Close the door.
If the jam is in the mailbox bin, then remove the jammed paper.
If necessary, press on the control panel.
Lexmark MS71x ? Troubleshooting 203.01 Paper Jam Error
The printer posts a 230.03 paper jam error with the paper stopping at the rear door. See this article for troubleshooting steps.