What are you supposed to do when your printer says "Jam Tray 1" and there's no paper jam to be found?
We have this Brother HL-3170CDW printer:
(It's a great printer: fast, prints duplex and reasonably priced. Although, a bit big and heavy.)
And it stopped working due to a paper jam error and despite not finding any paper jammed in it, it still claimed it had paper jam. The manual was unhelpful in solving the problem. Web searches didn't provide a solution. I emailed Brother support, and they gave me the solution.