Brother HL-5250DN printer paper light won't go off

I had the same problem on 4 Brother HL-5250's, I checked the whole printer, and couldn't find a paper jam, yet the red printer light wouldn't shut off. I finally followed the instructions on Brother's website for removing a paper jam, and the solution for all 4 printers was paper stuck in the fuser cover. See below on how to open the fuser cover.

Pull the tabs at the left and right hand sides toward you to open the fuser cover (1).

1. 
2. Hint
3. There are 2 kinds of covers at the rear of the printer. Please make sure to open both the back cover (step 7) and the fuser cover (step8).

I had the same problem. I looked for all possible paper jams, then opened the back and pushed the little levers in to release a flipper unit near the drum. Voila, next to the drum was a crinkled sheet of paper. The green light is back on and duplex printing is working!

I had found that strangely some Word documents failed to print and would constantly make the "no paper" warning come on even when there was loads of paper and no paper jams I could find. Then I discovered that in the Word document (in File > Page Setup > Paper) the offending documents "manual" in the paper source for the first and or other pages. If I change these to default/auto select then bingo it prints. I guess if you have it set to manual, the printer is waiting for you to manually feed it a sheet of paper from other than the paper tray.

Here's another wrinkle re. Solutions 2 and 3. All the settings per above were ok, but in trying to print an envelope from the auxiliary tray, it gave the paper error. After investigating a bit, I noticed that the printer was set for "duplex" printing (left over from a previous document). Duplex is incompatible with auxiliary tray printing, and instead of saying so, it just gives the "paper" error.

Buy a Lexmark.

I am on my third and last Brother printer THIS YEAR.

No more.

One didn't last even 3 weeks.

HI. My printer just did the same thing it was driving me crazy. I called Brothers tech support. The document you were trying to print sent your printer into the manual feed option. Bring up the document you're trying to print. Click on File then Print Setup. Click on Paper and change the setting to Tray 1 (if more than one page change in both columns) Then press OK. Press print and it will print for you. Tech said they dont know why some documents are doing this but it works every time. Good Luck!