I’m somewhat familiar with power losses, living on an island in Puget sound which has a seemingly single connection to the grid. And yes, sometime they change settings, due, I suspect, to things not being ‘clean’ always, when the power comes back on.
I’d be tempted to check the TV and the Sonos for updates, and apply them if there are any. Then, I’d unplug both the TV and the Sonos from power. As a safety precaution, reboot your router. Wait two minutes, then plug in the TV. Wait another two minutes, then plug in the Sonos. Wait yet another minute or two for the Sonos to boot up, then test. Make sure the content is in Atmos, of course…a recent movie on a channel that provides Atmos content. Most TV shows don’t.
If it still isn’t working, I’d submit a system diagnostic within 10 minutes of experiencing this problem, and call Sonos Support to discuss it. Don’t post the resulting diagnostic number here.
There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.
When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.
