Follow the steps below to clear the message:
The corona wire(s) on the drum unit needs to be cleaned. Clean the corona wire(s) in the drum unit.
The Drum unit is not installed correctly. Remove the drum unit, remove the toner cartridge(s) from the drum unit, and put the toner cartridge(s) back into the drum unit. Reinstall the drum unit in the machine.
If the issue still continues, the drum unit is at the end of its life. Replace the drum unit with a new one.
DCP-L3551CDW, HL-L2300D, HL-L2310D, HL-L2340DW, HL-L2365DW, HL-L2375DW, HL-L3210CW, HL-L3230CDW, HL-L5100DN, HL-L5200DW, HL-L6200DW, HL-L6400DW, HL-L8250CDN, HL-L8260CDW, HL-L9200CDW, HL-L9310CDW, MFC-L3710CW, MFC-L3770CDW, MFC-L5755DW, MFC-L6700DW, MFC-L6900DW, MFC-L8690CDW, MFC-L8850CDW, MFC-L9550CDW, MFC-L9570CDW