Try any of the following techniques to correct why does Brother printer keep going offline problem.
1. Check the Printer connection
2. Text the Printing Status
3. Make sure you are using the Print Spooler service
4. Update Printer Driver
5. Use it through Microsoft Fix it and check
6. Follow the troubleshooting steps and verify
7. You can try uninstalling the driver and installing the printer driver, and then verify
8. Make sure your Printer is in the same range as standard Printer