OK, thanks for responding readily to my inquiries.
If the problem might possibly be owing to aging roller surfaces (for paper is fed into faxes and printers with rubber or plastic cylindrical rollers, that propel the sheet into the machine)... then you might need to clean the rollers in the problem area where feeding-in of the paper is done.
Remove all paper from the machine, unplug it, and open it so as to have access to the rollers in the problem area where feeding may not be being done properly.
Take a clean high-quality lint-free rag cloth, moisten it with rubbing alcohol, and rub the rollers firmly all over their paper-contacting surfaces, three times over.
(Note: do not ever touch nor rub nor clean the shiny, blue-ish metallic-looking 'roller' or 'drum'... that would merely damage it permanently. It is not involved in the problem your copier is having, at all.)
(If the rollers are hard to reach, there is another way to clean them... let me know if that is the case, and I will detail how to do the cleaning.)
Allow 5+ minutes for drying-off, then reload the paper, close up the machine where you opened it up, and then try again.