When trying to print with your Brother label printer, the Status Monitor warns “The media installed in the machine does not match the one selected in the application”, and the printer flashes a red light near the power button. The printer refuses to print.
For example, this happened on my QL-1110NWB.
- Go to Settings → Bluetooth & devices → Printers & scanners, and click on your Brother printer.
- Click on Printing preferences to bring up this window. (It’s crucial to open this Printing Preferences window from the Settings app instead of from any other program, because only the Settings app configures the default printer settings — otherwise the settings do not persist across applications or sessions.)
- Select the correct paper size. For 4×6″ shipping labels, you should actually choose “4 x 6” instead of the default “4.07 x 6.4”.
- Click OK to save the settings.
- Restart the printer to clear the error, and try printing again.
Thanks to my friend Larry for figuring this out with me!