The printer cannot read the installed optional interface card.

Turn off the computer, then remove the card. Make sure the interface card is of a supported model.

The paper guides are not set correctly.

Make sure that the paper guides in the optional paper cassettes are set to the correct paper size positions.

The optional paper cassette may not be installed properly.

See Optional Paper Cassette Unit for instructions on installing an optional paper cassette unit.

The paper source setting may not be correct.

Make sure you have selected the proper paper source in your application.

There may be no paper in the paper cassette.

Load paper into the selected paper source.

Too many sheets may be loaded in the paper cassette.

Make sure that you have not tried to load too many sheets of paper. For the maximum paper capacity for each paper source, see MP tray, Standard lower paper cassette, and 550-sheet/1100-sheet Paper Cassette Unit.

The paper size is not set correctly.

Make sure to set the paper guides in the optional paper cassette correctly.

The paper is jammed at the optional paper cassette.

See Clearing Jammed Paper to clear jammed paper.

The installed option is not defined in the printer driver.

For Windows users:
You have to make settings manually in the printer driver. See Making Optional Settings.

For Macintosh users:
When you have attached or removed printer options, you need to delete the printer using Print Setup Utility (for Mac OS X 10.3), Print Center (for Mac OS X 10.2 or below), or Chooser (for Mac OS 9), and then re-register the printer.