The problem started when I opened the Youtube app on the TV and then found that the videos could no longer be loaded. Then I went back to the satellite TV, where the channels suddenly stopped working. It shows the respective program the whole time, what is currently running, but without sound / picture.
I've already tried to re-initialize the problem, but it didn't work either.
Now the television can almost only be switched on via the Amazon Fire Tv Stick, with which I can also watch Amazon Prime, Netflix, etc. But when I switch back to satellite TV, the picture / sound doesn't work again.
Before "experimenting" any further, ask SONY support first - they were able to help me with a problem with BT headphones.
