MX Linux is great at finding printers but some might need some config.
If you don't use Linux regularly it's easy to forget this.
Open a web browser and go to "http://localhost:631/printers".
Click "Modify Printer" and set following parameters.
- Your device will probably be shown already as "discovered"
- lpd://(Your printer's IP address)/binary_p1 for Device URI
- Brother for Make/Manufacturer Selection
- Your printer's name for Model/Driver Selection
Be sure to scroll through the list and select your printer even though it looks like it knows the right model because it was shown as device.
Try a test print
You can always go to the Brothers site and download the deb cups driver and install but it should not be necessary.
My MFC=7840W was a pig to get going until I found the access to the cups admin page and did the above settings.
Previously MX always grabbed the printer and worked without accessing cups admin so I was spoiled.
Obviously, if running in a virtual environment the network can not run NAT or it will not be on the local network.