​Every 10 minutes or so, a box shows up in the bottom right corner of the tv and says, "No input detected. The TV will turn off in one minute."  The TV reception is just fine, so there must be a signal.​

I go through an entrie restart, and then 10 minutes later it starts all over again.​ This has happened with Netflix, Prime Video, and if I remember right, I first noticed it on HBO Max.

As far as I know, nothing had been changed before this, and all of my internet connections through computers and iphones are just fine. I've had the same hardware (that has worked just fine) for years.

As far as I know there is no problem with any of my cable channels.

I called Xfinity, and I could not get through all the "service prevention" screening (Is there are worse organization for customer service?) they throw at me, so, of course, I could never talk to a live person.