Quoting from another model at link above:
DescriptionPrint faxes received in memory when the paper size loaded in the machine does not match the PAGE SIZE menu. You must press to clear the error then print the fax from memory.
SolutionMemory ReferencePrint faxes received from memory when the paper size in the machine does match the PAGE menu. You must correct the paper size discrepancy, press to clear the error and then print the fax from memory
.Check / Change Paper Size:
Confirm what size paper is loaded in the rear tray (A).
The above illustration shows a PIXMA MX310
If the paper size loaded in the rear tray is not what you would like to be loaded, verify the paper size you want and then install it.In FAX mode, the machine will only support three paper sizes, 8.5"x11" (letter); 8.5"x14" (legal) or A4.Press to clear the error and return to standby mode.Press the button.Press the button.
PAGE SIZE screen will appear.
Use to select the paper size that matches the size loaded in the rear tray.
The choices are 8.5"x11" (letter); 8.5"x14" (legal) or A4.Press the twice.Click here
to print the fax from memory.Print From Memory:
Press . to select to print all pages of the document.Press .
To print another document, return to step 6To finish printing, go to step 10.The screen will return to standby mode, if it does not, press .