Archer C9 V3.0 - can't turn on print server
I have an Archer C9 V3.0 router. Firmware is 1.3.1 Build 20171215 rel.35219(5553)
I want to use the print server function.
I plugged in my USB printer (a Brother MFC-8440) into the USB port on the router.
I downloaded, installed, and ran the "USB Printer Controller" software as described in the FAQ article at https://www.tp-link.com/en/faq-415.html
The USB Printer Controller program was able to see and connect to my printer.
But when I go to the router's print server configuration page, and click on the switch to turn on the print server, it remains gray.
Is this a bug with the C9 V3.0 ?