My Brother MFC printer shows a status error related to ink or toner. I replaced the cartridge, but the error persists. What's the problem?

Ensure the new cartridge is a genuine Brother cartridge or a compatible cartridge that's known to work. Clean the cartridge contacts with a dry, lint-free cloth. Reset the printer by turning it off for a few minutes, then turning it back on. Some printers require manually resetting the cartridge counter through the printer's menu.