Absolutely, 100% won't connect -- via Ethernet! -- after modem upgrade

Upgraded the modem to 1 gig.

"No players found." Was able -- after tech support conversation -- to plug each of my 2 units into the new modem directly (i.e., unplug from switches and direct connect) to work, rename new network, give new password, etc.. Was advised I could now safely move them back to their switch-ethernet connections in 2 separate rooms.

Nope. "No Players Found."

Unplugged/replugged, rebooted app on both phone and Mac. Nothing. Expensive paperweights.

Any insights appreciated; they aren't coming from tech support thus far. They've kicked-the-ticket upstairs for more expert advice.