PIXMA TR8520: Persistent error message: no paper in rear tray.

[shadowsports]

Greetings,

"PIXMA TR8520: Persistent error message: no paper in rear tray"

You haven't given us very much to go on.  

Does this error message mean you don't have paper loaded and the printer is trying to print from an empty tray?

or

You have paper loaded and the printer is not detecting the paper?

We need more information in order to try and assist you.   

[resawd21]

Sorry about that abbreviated post.  Couldn't figure out what to do after entering the subject.  I'm using and HP with W10 and a Canon TR8520 printer.  Printer wants to keep telling me that there is  no paper in the upper tray even tho I'm trying to print from the lower tray on letter size sheets.  If I put paper in the upper tray I can  print photos fine just can.t get it to recognize the paper in the lower tray.  As far as I can tell the sizes are properly set for both trays.  This a new problem, have been able to shift between sizes readily in the past

[resawd21]

Refining this a bit.  I can print from the rear tray fine.  If I leave paper in the rear tray and try to print from the cassette,it will print on paper from the rear tray not the cassette.  It seems to be hung up inb the rear tray.