Brother MFC-J6540DW printer: "clear paper jam" when there is none

I posted this question in a Brother users' forum and got no replies. Let's see if I have better luck here.

I have a Brother MFC-J6540MFC printer. I was trying to print an envelope from the single-sheet feeder.

When I told the computer to print, it replied that the printer had suffered an error. I tapped the printer's touch screen and it displayed five-step instructions for clearing a paper jam. But there was no paper jam.

When I reached the last screen it said, "1. Install the paper tray. 2. Press Stop X."

But there is no "Stop X." No button anywhere on the control panel that's labeled "Stop" or "X." I tried tapping "Stop X" where it appeared in the message on the touch screen, but that did nothing.

I tried to reset the printer by turning it off and back on. When I pressed the power button for "off," the touch screen said "Busy... try again later." The printer wouldn't let me turn it off. I had to reset it by yanking the power cord.

This happened to me several times, and it's messed up in every possible way. Why did the printer think it was jammed when it wasn't, and how can I prevent it from sending me into a recovery procedure with no exit?

Did you change the paper size and paper type?

My Brother has a button marked stop/exit, but it's not same model as yours.

Inkjet printers in general can detect a paper jam (when there is none) when one of the a small controller boards goes bad.

You can try removing printer/restarting PC/then reinstalling the printer but I don't think it will do any good.
Brother has excellent technicial support. You might give them a call.