The solution to the Brother Printer Offline Mac issue is demonstrated below. Ensure that your printer is turned on and powered. Make sure there is enough paper in the loading tray. Take out any paper clogs you find. See if there are any new issues with your printer.
Your Brother printer should be able to join a wireless network. Ensure the USB discs are inserted correctly into the USB ports and that your computer can recognise the printer. Remove the full printing queue as well. Make sure the firmware on your Brother printer is up to date.