What ate you sound output settings on the tv?
 

The Beam can only process the data it receives, and from your post it would seem the wrong signal is being sent to it. 

Try setting digital output audio format to Passthrough. You may also need to set the Dolby Atmos to On. 

Tank you for your reply, my digital output signal is on auto. I can't pick pass-through, it says: "the current audio format input cannot be passed through with an arc connection" .....and Dolby Atmos is on

Do you choose the original language version of the movie? Dubbed over versions often do not do Atmos.

Are you connected from tv to Beam using HDMI, eHDMI, HDMI-ARC, optical-to-HDMI? Standard HDMI will not work for Atmos, as I understand it (nor optical). 

Just a slight correction to @nik9669a post. The inputs on your TV should read as “HDMI”, HDMI ARC and/or HDMI eARC. At least that’s the way the inputs are labeled for TV’s in the USA market. I realize different countries may require different labeling.

Thank you guys, I've connected the HDMI cable into HDMI eArc and using the HDMI cable provided by Sonos 

Hi @106rally, Thank you for your message. Yes I choose original language version.

This whole thing is weird. My tablet shows the spatial audio sign on Netflix, but my TV doesn't.

I've talked with Sonos technician and it seems like the beam gen 2 combined wit era 300 is only supporting spatial audio for music, but not for movies 🤪 But he wasn't sure either and needs to check internally to confirm it later.

To be honest, the marketing makes you feel it also supports spatial audio for movies, what's disappointing.