The setup paper doesn't fit in cartridge.
The maximum paper size format allowed by this printer is International A4 size (210 mm × 297 mm or 8.27 in × 11.69 in). If you try to place paper larger than this size, then it will be impossible to print it. I also suggest checking the official specification for this printer using the manufacturer's page. You should see the exact paper format support as well as resolutions and other printing features.
Home page: http://www.canon.co.uk/Printers/Inkjet/PIXMA/PIXMA_MG5450/#p-specification2
