Please check the following points to solve the problem:

• The paper size defined in the printer driver is not supported by the defined tray.
  
  Press Cancel. Choose a paper size that is supported by each tray. For details of the supported paper size, go to Manuals section and check the User's Guide.
  
  
• The paper size defined in the printer driver is not available for automatic 2-sided (duplex) printing.
  
  Press Cancel. Choose a paper size that is supported by the automatic 2-sided (duplex) printing. The paper sizes you can use for automatic 2-sided (duplex) printing are A4, Letter, Legal or Folio.