Assuming Spotify is available in your Country on Sonos and that your online Sonos/Spotify country settings are set correctly for your location, then perhaps try the following.. go online and login to your Spotify account via a web browser and look for and sign-out of all devices on your account. Then remove/reinstall the Spotify App from your mobile controller device and finally do the same thing and remove reinstall the Spotify service in your Sonos App. Just ensure that when logging into your Spotify ‘account’/‘service’/‘app’ that you use the same login credentials. 
 

Then see if that solves your issue. If not, it maybe best to contact Spotify support, or perhaps Sonos Customer Care via this LINK

Have tried that already. Removed tha Sonos app from Spotify web and likewise the Spotify service from Sonos app. 

Have even tried reinstalling the app on multiple devices.

No luck. This issue has appeared around end of July/beginning of August.

Did you check your country profile settings and log-out of ‘all’ devices via the Spotify website and actually remove the apps? Also as mentioned, if you still have no joy, then perhaps give either Spotify or Sonos Support a call.

@arisaris,

I just use the free version of Spotify and have just tested it and it’s working okay here (see attached screenshot taken a few moments ago), so it is likely something to do with your account setup or location settings. So if it persists, after trying the things suggested, then maybe speak with the support staff

@Ken_Griffiths 

Thank you for your input. Will most probably check out the issue with support.