BROTHER Error Code 21

Error 21 on Brother printers typically indicates that the printer believes there is no paper loaded in the tray, or it cannot detect the paper.

1. 1

   Open the paper tray and remove all paper. Fan the stack of paper to separate any stuck sheets, then reload it neatly, ensuring it's not overfilled and fits snugly within the guides.

2. 2

   Verify that the paper type and size loaded in the tray match the settings selected on your printer's control panel or in your computer's print settings.

3. 3

   Gently clean the paper detection sensors inside the paper tray area. Use a lint-free cloth lightly dampened with water or isopropyl alcohol. Look for small plastic levers or optical sensors.

4. 4

   Ensure the paper tray is fully inserted and locked into place. Sometimes, a tray that isn't completely seated can prevent the printer from recognizing the paper.

5. 5

   Try using a different stack of paper or paper from a fresh ream. Old, curled, or damp paper can sometimes cause detection issues.

6. 6

   If your printer has multiple paper trays, try loading paper into a different tray and printing from that source to see if the error persists.

7. 7

   Perform a power cycle: Turn off the printer, unplug it from the wall, wait for 30 seconds, then plug it back in and turn it on.

8. 8

   Check for any small pieces of paper or foreign objects lodged inside the paper path or around the paper tray area that might be obstructing sensors.

If you've followed all the DIY steps, including cleaning sensors and trying different paper, and the Error 21 persists, it might indicate a more complex hardware issue. This could involve a faulty paper detection sensor, a problem with the paper feeder mechanism, or an internal circuit board malfunction. In such cases, professional diagnosis and repair are recommended, as these repairs often require specialized tools and expertise.