Casting dashboard to Vizio TV suddenly yields blank screen

Hi all, I have been happily casting a dashboard to my Vizio TV every morning for months now via an automation but in recent days it just stopped working. Specifically what happens is when I cast a dashboard to the TV, either manually or via automation, the home assistant logo with “Connected” appears for about 0.2 seconds, and then disappears and I’m left with a blank white screen.

The same casting works fine on other devices so I guess it must be something about the TV – I tried a factory reset (the only way to clear the cache, sadly) and that didn’t help. Any other Vizio owners with ideas here?