Why is my mac brother printer offline?
javing trouble printing from your Mac to your Brother printer, one possible reason could be that the printer is offline. This means that your Mac is unable to communicate with the printer over the network or through the USB cable. There are several reasons why your Brother printer might be offline. Check to make sure that the printer is powered on and that it’s properly connected to your Mac and to the network.
https://printersofflines.com/brother-printeroffline/#HOW_DO_I_RESTORE_MY_BROTHER_PRINTER_ON_MY_MAC