Be sure the HDMI Input Audio Format setting is set to Bitstream, not PCM.

If the Digital Output Audio Format set to Auto doesn’t work, try setting it to Dolby Digital Plus.

Thanks for the reply!  There is no HDMI input audio format setting.  Went through the menu everywhere and do not see it.  The digital output audio format setting only has auto or PCM to choose from and pass through is grayed out and will not let me select it.  I see other issues with Arc and Samsung TVs,  but I also see that some can get Dolby Atmos with their Samsung tv.  Feel like I’m missing something.  

What specific content are you testing? HBO Max has limited Atmos content. Also, I don’t think Atmos is supported on the native HBO Max app on Samsung TVs.

Read more about supported devices here: https://help.hbomax.com/Answer/Detail/2957 

Have you tested any Atmos content on Netflix? If testing Netflix, be sure you have a Premium Netflix subscription and the Streaming Quality is set to High or Auto.

I am trying Justice League, Wonder Woman and anything else that has the Dolby Atmos logo next to the title.  My understanding is if it has Dolby Atmos next to the title, it is supported, right?  I knew about Netflix needing the premium subscription which I do not have, so I have not even tried that.

If you are using the native HBO Max app on your TV, Atmos audio isn’t supported yet on your TV. Read this article: https://help.hbomax.com/Answer/Detail/2957

You freaking genius!  Just looked up something on Amazon Prime that is supported and tried it.  It’s working!  I’ve tried Sonos support and they were stumped and I have been googling and YouTubing for 2 weeks trying to figure this out.  Thanks my friend!