Sony Bravia TV will not display Apple TV screen

Until recently, my Apple TV 4K (1st generation) worked fine with my Sony Bravia TV. I was away for a while and upon my return, the Bravia will not display the Apple TV screen. The screen is just .... black.

I have repeatedly checked the setup, tried multiple different (high speed) HDMI cables (including the ones that worked before), switched inputs, etc. I even bought a new Apple TV 4K (4th gen) and tried that with multiple cables and multiple TV inputs. The Apple TV device will turn on (and turn off) the Bravia; the Bravia even recognizes that Apple TV device is plugged into the corresponding HDMI input.

But the screen remains steadfastly black. Was there some software update to the Bravia that has caused a compatibility issue?