Series 8 - not recognizing sound bar

[Th297477]

I have an older Series 8 TV. UN65KS800D

I have the soundbar out connecting to  HDMI 4 (ARC), and the anynet+ enabled.

I don’t get an option to use HDMI ARC in the sound settings

I have done a factory reset and it didn’t help. I have switched HDMI cables. 

When I have an HDMI in to the soundbar, with HDMI out the TV plays the video, so there is a valid connection, and the TV recognizes the connection.