Update: without any changes performed on my end it started to work yesterday. Maybe the Sonos technical team fixed a technical error with the Webservice calls to Google Servers. See below:

I’ve got the same issue - still not solved.

I’m asked to update my Sonos app (which it is), and I’m stuck with that message. It used to work, but suddenly it doesn’t…

Same problem here! Bought AMP, beam and google nest. Plug and play, Everything worked fine and all of sudden I got the same message as u guys… 

Same problem here on my Sonos Roam - still no solution… pretty disappointing. Only Sonos products does NOT “works with Google Assistant”.

What did they say, when you called Sonos Support directly to discuss it?

They probably still waiting on hold or didn’t receive a response

Was told by Sonos support that this is a known problem with the Sonos Roam - which I bought specifically to use with Google Home.  The speaker will be returned for a refund.

You dodged one there, return it ASAP Roam is not a reliable product. 

Just like in my case, I bought the Sonos Roam because of the Google Assistant and because I wanted to try out Sonos. I can rule out that the issue lies with Google because the same problem occurs when trying to set it up with Amazon Alexa. The support also informed me that there is a known issue that they are working on. However, they couldn't tell me whether a software update would be available in a few days or only in weeks/months.

I have done a lot of research on this topic, and it seems not to be just a problem with the Roam, as exactly the same issues were reported on the One as well, and forum entries date back to 2021. Therefore, I had little hope that a solution would be forthcoming anytime soon. However, I read a few times that if you keep trying, it might work eventually - without any software update. And that's what happened to me today. After more than a week, I was able to successfully link the Google Assistant. I will keep it for now because, aside from this issue, it is an outstanding product. However, I won't buy any more Sonos products for the time being. I actually wanted to upgrade the living room with Sonos speakers, but if there are also such problems with the Assistant, it would be extremely annoying, considering the very high price.

Thanks for the update.  I bought the speaker as factory refurbished from the offical Sonos store on ebay.  I am trying to return the speaker and Sonos say they have sent me a pre-paid returns label, but I have not received it (only the partial returns address, which is in Poland). 

A product that doesn’t work as advertised, and poor customer service.  My first and probably last Sonos speaker. 

It stopped working on the same day. What a disappointment, shame on Sonos. I wish I had checked the app reviews before buying a Sonos Product.

Same error message on my old Beam Gen1, AND my new Move2 and Arc..
Fillin in everything and on the Sonos Side of things it requests me to Update either Google Assistant or Sonos app. 

On google side of things it says my system is not connected to my account. (which it is.) 

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On a sidenote i cant get the “skills” in Alexa to work either. Only get sonos own voice activation to work sadly. 

I believe that Sonos shows an indifferent attitude towards this issue. Despite the lack of a solution and numerous customers facing the same problem, this request is marked as "ANSWERED". It is profoundly regrettable that a company of such renown considers such a matter as "concluded". Such business practices are deeply disappointing.

Still have same problem here. Device registered and everything is updated/reinstalled

So, I sent it back. Never again SONOS products. Vote with your wallet.