Im having a bit of a problem getting my TV to output sound for both Amazon Prime video and Netflix through the optical port. There isn't a problem when I have it set to output through the TV, but when I turn it to optical it just cuts. All other streaming services work just not these two. I've checked that it isn't set to 5.1 Surround as the DAC I'm using doesn't support it as well as rewiring the entire sound system to insure that there isn't an air gap of some kind.
Does anyone have a suggestion? Sound really isn't my area of expertise so sorry if there is a glaring answer that I haven't noticed.
The first thing I'd check is that your optical cable is of good quality and both ends when plugged into each source individually has the tell-tale red light. I would also verify that your sound bar, or speaker has the compatible decoding type as your tv. To ensure this the PCM setting in Expert mode should be set to all. You can get to it like so (Sound > Expert Settings, HDMI Input Audio Format must be PCM instead of the default Bitstream).This is covered in the attached post here,
Hope thos helps! If I solved your issue, please mark it is solved. Have a great day!