sonos surround sound not playing with samsung apps (HBO, Netflix, Amazon, etc.)

I currently own a Samsung UN75MU8000F and have my Playbar, Connect:Amp, and two Play:1s set up in my family room. The Playbar + Play:1's are set up as a "surround sound" set up on sonos system. When playing normal TV, my surround sound works perfectly (aka all three speakers play sound). However, the moment I turn on one of my TV Apps from the smart TV's menu (i.e., Netflix, HBO, Amazon), no sound whatsoever comes out of any of my sonos speakers. At the moment the only way I can watch those apps with sound is to switch to using my actual "tv speakers" rather than the Audio Out / Optical option (i.e., the output that plays my sonos speakers).

Any idea what would cause this issue specifically when switching to using my TV apps / how to fix is? Worth noting that before I installed the Play:1's and set up "surround sound" I had no issues with any of this...my plabar worked just fine no matter if I was watching regular TV or using HBO / Netflix / Amazon, etc.

Any help would be great. Thanks!