Affected Products:
Single-Function: B2650, B2865, M5255, M5270, MS725, MS821, MS822, MS823, MS825, MS826
Multifunction: MX722, MX725, MX822, MX826, XM5365, XM5370, XM7355, XM7370
Issue Description:
A 230.03 error indicates paper fed from the Multipurpose Feeder (MPF) never reached the duplex path sensor.
The printed pages are stuck behind the Duplex Module.
Solution:

Remove any pages stuck in the duplex tray.

Remove the duplex tray from the printer and look in the cavity for a sheet of paper to be removed.
Explanation:
Errors can be cumulative that failure to resolve one error can actually cause another error.
In this case, a failure to completely correct a 202.xx error may leave a sheet of paper stranded in the paper path in the lower section of the redrive, and near the duplex entry area.
As a result, the stranded sheet prevented entry of all additional pages into the duplexer.
Still Need Help?
Have the following available when calling Lexmark Technical Support;
Printer model(s)
Printer serial number
LEGACY ID: SO8597