Remove the cassette and adjust the silly little sliding paper size thingy. Mine somehow ended up on A4 or something when it should have been on LTR. Whatever size you select has to match the settings so go to: settings- device settings- scroll down t...
So I have a different printer (TS6120) but I got the same message and had the same issue-my solution: look in your cassette and move the sizing piece to LTR. If that doesn’t work try them all. Mine was set for A4 somehow. I was so stressed I almost t...