I had this problem as well. The sound bar needs to be set to adaptive not d.in as this is no longer an available. Once you do that go into the settings on your TV go to sound and tap the middle button on remote until tv + sound bar is selected. I think it's the 3rd setting
Hi I just fix it a few hours ago , you have to update your tv , maybe it’s already updated but the soundbar need to update it too, so I updated the soundbar in the app SmartThings and it that was it .
