Yesterday I suddenly found that I could not print to my Brother MFC-J6720DW from my MacBook Pro (running Mac OS 10.12.6), nor could I use the scanning function. The other Mac on the Wi-Fi network cannot print on it either
The printer was connected by Wi-Fi and as far as I know nothing has recently changed on the network. My laser printer on USB is working fine.
I have reset the printing system as advised to another person who had a similar problem. However, when I try to add the MFC printer I get an error message. So, I connected the printer to the MacBook with an ethernet cable and found that I could now add the printer and actually print to it.
However, I cannot figure out how to add the scanner functionality. I downloaded the latest scanner driver from Brother & installed it, but I can't see how to add the scanner to the printers/scanners list. (I had no trouble adding my transparency scanner which is on USB.)
I'm sure the answer must be really simple but I'm somehow missing it. It would be good to know why I can't add the printer over Wi-Fi - I could connect to it with Safari and interrogate the administrative functions over Wi-Fi.