Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
Unplug the printer from the power, sharply and suddenly, while it is On.
Leave it that way for 1+ hour, and only after that time, plug it in again.
Then see if the error has cleared. Also, if it does not, check the printer's status, esp. toner level, using the Brother software that came with it.
And, remove the toner cartridge, check it briefly for signs of leakage of toner, and shake it gently a little, then put it back into the printer, close up, and see if the error has cleared.