I came here after searching for an answer to this, April 2020.

Trying to trigger a simple morning routine like

1: switch on all LIFX lights

2: play a playlist

from my Move or Sonos One and Alexa immediately replies with this “Audio actions not supported”...BUT she does run the routine, the lights come on and the playlist plays.

I see no way to set what room or Sonos device to have Alexa play the music from, but it seems to play fine from every room and the Alexa routine does work fine.

The error message doesn’t seem to stop the Alexa routine from running. It’s just very clunky and awkward to listen to an error message every morning after running the routine.

seems this should be fixed by Sonos by now. If you advertise Alexa support or Alexa works with this device, then it’s misleading when it does not work.

As a work around, I use IFTTT for the playing of a Playlist within a Routine which stops this annoying message.

My post here shows how to set-up IFTTT for a different issue with BBC radio stations but the same approach will resolve your issue: https://en.community.sonos.com/amazon-alexa-and-sonos-229102/step-by-step-guide-to-play-bbc-radio-station-via-voice-control-6834993

Just insert your Playlist instead of the radio station in each step.

Before I also had some routines that worked and also had the "“Audio actions not supported” message, 

but after trying out the google assistant I reverted back to Alexa, but none of the routines work anymore, even the standard routines do nothing.

I hope someday full routines support will come out.

I suspect that this isn’t a Sonos issue.  Have you opened the routines and checked that the Actions are still correctly listed?  Sometimes Alexa will delete Actions when a Skill is removed.

Apart from de-registering the Sonos speaker from my Amazon account, I've tried everything.

(Deleted the Alexa app, deleted the Sonos app, installed everything again. Still didn't work.)

Have you tried Disabling then Enabling the Sonos skill in the Alexa App?

Yes.

If you create a new routine does that work?

No.

New, old and standard don't work.

Strange, all of my routines work fine - sorry, no help to you!  Do these routines work on an Amazon Alexa device?

No problem, I guess the only option would be a factory reset or de-registering the speaker from the amazon account.

I don't have an Alexa device besides the Sonos One.

But all routines work on an Alexa device, but not on Sonos, because Sonos doesn't have full support for Alexa. Not all features work.

Strange that it did work before the switch to google assistant.

Before I would simply use the standard routine and said "Alexa, good morning" and it would give me the news from my flash briefing this day in history , when I try that now she replies with "good morning" and some trivia.

Anyway I'm managing routines now with ifttt as a workaround.

Don’t factory reset your device as this will remove all diagnostic information.  With regard to your flash briefing, can you open the Alexa App>Settings>Flash Briefing and check the content and order of items are as you require?

Yes, I have a skill for the flash briefing for VRT News.

Also I've used the "Alexa, start my day routine" before the switch.

But as you know, those routines don't work anymore

Greetings everyone,

We do not have any timeline to share on when or if these changes will be made. While routines may or may not run as expected, they are still considered unsupported and when I mean by unsupported, that doesn’t mean it won’t work, it is that we cannot effectively troubleshoot it.

Lastly, I think it's important to remember that we do not have anything to do with features both supported and unsupported on this platform. As Alexa voice service is owned by Amazon, supported features and services would be decided by Amazon.

Have you checked if this is not a matter of implementation of the new "InteractionModel interface for the Alexa Voice Service”?

Amazon announced this new interface in August 2018 on their developer blog here:

https://developer.amazon.com/blogs/alexa/post/a1470f4c-8aaf-4d12-b3bc-5cf38820ff82/alexa-it-s-bedtime-routines-for-avs

However Bose had this same issue with Routines and they actually have fixed it? Why is it that you are saying it’s not a Sonos issue and it’s an Amazon issue? It does appear to be something that could be fixed - there are many posts on Reddit and elsewhere that explain Bose fixed Alexa Routines a year ago on their integrated smart speakers, so it does beg the question why Sonos don’t see this as their issue or as something they can fix?

Actually, routines stopped working on Sonos at all quite recently, see here

This sounds more like a definitive answer that Sonos is not going to implement the routines which is a huge drawback.

Basically this means to get maybe 20% of the “now with Alexa” functionality on the box and in the advertising from Sonos you effectively have to buy an Echo.

If I set up a routine in Alexa for “Good Morning” to turn on my lights, tell me the weather, read me the news headlines and then play a playlist it immediately fails on the Sonos One.

Sonos responds “audio not implemented” for the playlist, and then says “here’s you flash briefing” and nothing plays.

Oh but the lights come on so yeah 1 out of 4.

For anyone invested in the smart speaker ecosystem, routines would rate absolutely crucial. I’d love to see many real world use cases for the current Alexa implementation (or lack thereof) on Sonos.

It is a massively hobbled implementation, and it effectively drives users who do want smart speaker integration to buy an Amazon Echo or Show to get it. That seems crazy to me. Don’t encourage your users to buy the competition product.

S2 OS is still affected with this bug.

@Sebastien D.: when can we expect you would fix it and provide the advertised functionality?

Note, that this is most probably issue on your end. As mentioned earlier by @danellisuk Bose has managed to fix it very quickly.
Check the link provided by him:

https://developer.amazon.com/blogs/alexa/post/a1470f4c-8aaf-4d12-b3bc-5cf38820ff82/alexa-it-s-bedtime-routines-for-avs

It’s sad to hear the new app and the new upgrades done to the speakers when you upgrade to S2 still doesn’t fix this.

Is there? Are you talking about the FllT workaround or adding the room name into the audio section, I did the latter and I still get the annoying not supported messages then it plays the audio from the routine

Come on get it fixed

Yet Sonos can use the Amazon and Alexa logos, and proudly put on the box and all the marketing “works with Alexa”. To me that’s embarrassing for Sonos to keep claiming they can’t fix this when other players like Bose can and have.

happy to claim it works with Alexa...just not happy to actually make it work. Sad.

This lack of elegant compatibility with the full Alexa feature set is annoying. Is this also the reason Sonos speakers don’t show up as devices that are available to set up as “actions”  in the Alexa app’s Routine section?

I have an Alexa motion sensor and I was hoping I could set it so that the Sonos speaker in that room unmutes only when there is motion.  And mute again 5 minutes after there is no motion.  Is that possible with Alexa and Sonos currently or do I need to integrate a Smartthings hub (or similar) to make this happen?