Why network printer doesn't connect to my XFinity router?

I recently changed from an U-Verse controlled network, to XFinity -- and my MFC-9120 stopped working. It used to register itself on the network as BRN001BA95xxxx, but I don't see that anymore on the XFinity side (though I see flashing ethernet lights on both ends of my network cable) . I'm plugging the printer into a Switch, that sits under the Modem/Router, but the other devices that are successfully connected to the switch / internet can't see printer either - and BRN001BA95xxxx doens't show up on the Modem Connected Device list at all.

I've tried reconnecting directly to the modem directly -- device still doesn't show up as connected device. Also tried doing Menu / Network / Reset Network / Reboot on the MFC-9120cn, and that did nothing either.

Ideas?