I have a Samsung UN55K8500 TV. I also have a Samsung HWA650 soundbar. The two work fine with the Slimline Remote 2 for a few years. Suddenly, the remote wouldn’t turn on/off the soundbar. When I used the soundbar remote, to turn it on, I couldn’t control the volume or mute with the Optik remote.
I rebooted the soundbar and it now comes on when the TV is turned on. However, it still will do nothing to the sound. (I am using optical input.)
I have used various codes to try and program the Optik remote but to no avail.
As I mentioned, up until about 2 weeks ago, everything worked well.
In terms of changes, there hasn't been any software updates for a while, especially not in the past 2 weeks. Is it possible there was a Samsung update pushed out to the TV that may have caused the issue? Can you try rebooting the TV through it's system settings to see if that helps? Failing that, try unplugging the soundbar and reseat all the cables.