The error message "Paper Size Mismatch" or "Wrong paper size" is displayed when the paper size setting does not match the size of paper in the tray.

Or, you did not set the paper guides in the tray to the indicators for the paper size you are using.
 

If you are printing from your computer, make sure the paper size you selected in the printer driver or in the application you use to print matches the size of paper in the tray.

1. Check that the paper size you selected in the machine matches the size of the paper in the tray.
   If you are printing from your computer or mobile apps, make sure the paper size you selected in the printer driver or in the application you use to print matches the size of paper in the tray.
2. Make sure you loaded the paper in a Portrait position, by setting the paper guides at the indicators for your paper size.
3. After you have checked the paper size and the paper position, press MONO COPY or COLOR (COLOUR) COPY.