Paper size

am running Office 365 Windows 10.  we have a shared multifunction Xerox Altalink C8155.  For 1 particular spreadsheet I cannot select "11 x "17 paper.  In is an option and I can use it or other spreadsheets but for this one sheet when I select it it defaults to custom and looks for 7" x 10" paper.  This is a spreadsheet I update quarterly and have never had this issue before.  Any ideas would be appreciated.