Can't print from my iPhone

[kishkes]

For my PIXMA G7020, when I try and print remotely from my iPhone, the printer tries to use the rear paper tray and gives an "out of paper"  message. No trouble printing from PC's on the network, which print from the main tray. What to do? Thanks. 

[shadowsports]

Greetings,

Your mobile devices might be telling your printer to use the rear tray.

or

The paper type you are selecting is set to feed from the rear tray.

[drbool]

So how do you change that?  I can't find it in setting anywhere.