I have a Samsung TV model UE55KU6670U. Commands that used to work now show the words on screen, then it comes up "I failed to recongnize what you said". Commands like these no longer work:
"Turn off TV in 1 hour"
"YouTube 4K video" (ie. search YouTube for 4K video)
This is terrible as we can no longer search YouTube or the Internet without typing using the on screen keyboard.
However some commands still work such as: "Volume Up", "Volume Down" and "Mute"
As the TV can clearly display the words I say this would seem to be a problem at Samsung's end. Yes I have full internet connection and latest software update.
This is the exact same problem that has happened to me today, has been fine any other day.
Basic commands such as Spotify, Wwe network, BBC iplayer, the time are not being recognised even though when I say it it shows exactly what I said.
I'm using KS7000 (UK)