Are you using a ‘free’ (with ads) Spotify music service - if so, then you need to upgrade that to a paid subscription to begin playback on Sonos via Alexa. The music service needs to be installed in both the Amazon Alexa and Sonos Apps and set as the default music service - also check you have setup your Alexa ‘enabled’ groups correctly for playback on your Sonos speakers.

Please see example Alexa group attached… showing the attributes of each section of the Amazon groups.

The first section is used to control the grouped speakers, the second section is used for ducking the audio on non-controlling/enabling speakers and the third section is the speakers (one or more, up-to 10 Sonos rooms) used for playback.

In the third section, set the playback options to ‘Always’ to playback without having to include the name of the group in the voice instruction.

@Ken_Griffiths Are you sure Ken? 

https://support.sonos.com/en/services/spotify

@UKMedia, I think that’s the case, yes …to start playback of Spotify audio on Sonos using Alexa, I believe it requires a paid subscription. Every service however, including the Spotify free service, once music is playing will allow you to use Alexa to start/stop tracks or raise/lower/mute volume etc. but to start playback of any album, artist, playlist etc., it needs the Spotify paid subscription service. I believe that’s always been the case. I think some radio stations may play for free, but generally, a subscription is required for initiating playback.

Unless something has changed in more recent times and I’ve missed the announcement?

@Ken_Griffiths The Link below states that it’s possible with the free version but with some limitations.  I believe that it changed in 2019.

https://www.amazon.co.uk/Spotify/dp/B07FK56GVY

The message the OP mentions is normally a network connection issue, so I’d recommend:

Ah so Alexa will play something, but a user won’t get a specified album, artist or playlist to play - is that the case then @UKMedia? I thought it just didn’t play. If that’s the case then yes it is probably a network or setup error as you say.

I’ve just added Spotify free to Alexa and Sonos Apps and this is what I’m getting…

"Alexa, play Peter Gabriel from Spotify”  (I included the Spotify service in the instruction, rather than set it as my default service) and it does play a ‘Peter Gabriel radio station” - albeit it starts with ‘Lavender’ by Marillion and not directly related to PG - so yes it should begin some kind of ‘radio’ playback and I stand corrected. - thanks @UKMedia 

Yes, I believe that it creates a playlist based upon the artist requested but not exclusive of that artist..

Thanks, @Ken_Griffiths  I have paid subscription with Spotify. It was all working fine for at least a year until about 3 months ago when this issue started happening.

I’ll re-check my enabled settings and let you know. 

Hi @User467655 

Welcome to the Sonos Community!

Please try removing the Sonos skill from Alexa, then add it again: Alexa app » More » Skills & Games » Your Skills » Sonos » Disable Skill, and once done, Enable to use.

If this does not fix it, I recommend you get in touch with our technical support team who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.

I hope this helps.