I've yet to find a fix for issues like this. Unlike a smart phone, PC or such things these Smart TVs have very little in the way of fixes. If you see a failure like this, the usual fix is to use the TV as a TV.
To cast to it you go get a Chromestick, Roku or such.
I've bought a film on Google play and am trying to watch it on my TV in the YouTube app (it seems my TV is too old to get the Google Play app, but does have YouTube by which I can access Google Play movies). It's the first time I've tried this. The sound of the movie is rather shaky and within a few seconds the sound disappears. The picture is fine.
I can watch YouTube clips on my TV fine, with no issues with sound. It seems just the higher quality Google Play movie doesn't work.
I've also tried casting the movie from the YouTube app on my phone to my TV, but get exactly the same problem. The movie plays fine on my phone and laptop.
My TV is model T27D390S. The YouTube app version is bbc829a7.
Please can anyone help me? This is the first time I've posted in a forum like this, nothing I've read so far has helped.
Thanks very much