Dell Latitude does not see xFinity WiFi network

Installed our new Xfinity Gateway Modem/Router xFI TG02DCW4482CT.  It replaced our owned Arris cable modem SB8200v2 and Linksys router WRT3200ACM.  After activating it  using our old SSID and WPA2, all devices connect with ethernet and WiFi except a Dell Latitude E6540 running Windows 10 Pro.  A HP laptop also running Windows 10 Pro sees and connects to the wireless network just fine.  Both are running Win 10 Pro with the same fixes.  Also both run McAfee if that matters.  The Dell has an Intel AC 7260 dual-band wireless adaptor running its latest driver 18.33.11.2 from 10/31/2017.  The only adapter setting changed is Preferred Band to 3-5 GHz.  This Dell works fine with the old Arris/Linksys setup.

Texted with Xfinity support Ayush for an hour and got nowhere.  My circumvention is connecting the old Linksys WRT3200ACM to an ethernet port of the Xfinity xFI got the Dell connected.  I checked the network map of the Linksys and see just the Dell.

I also can't connect the Dell at 2 other houses that have xFI modem/routers.