Cannon laser fax 1060 P "check paper size"

Hello, our office has a Cannon Laser Fax 1060 P that is constantly giving the error message "Check Paper Size". The alarm button blinks and when I press "stop" it prints out as many as 5 to 10 of the confirmation pages. No one in the office can find the manual. I think when the machine was moved to our office, someone pressed a button while moving the machine that is causing the problem. Before the machine was moved, it was working perfectly. We can send faxes, but receiving faxes is a real problem. Would you please tell me how to "check paper size" so we can get and send faxes again. Thank you very much, Take care,. Margaret