Sonos/Spotify problem - The spotify account login information is not valid

[DominicP]

My Spotify premium account no longer works with my Sonos system. It did until about a week ago.

I get an error message each time I try to play a song.
"Unable to play XYZ - the Spotify login information is not valid"

Having gone through many , many suggested online fixes (clearing cookies/resetting password/ deleting and reinstating on Sonos etc) it still doesn't work.

I have been in touch with Sonos who have remoted in to my computer and tried their Spotify account on it which worked. The problem appears to be with the Spotify account...

Help 

I am sick of trying to fix this.

[Peter__]

Is your account still showing as Premium with a renewal date in the future here?:
https://www.spotify.com/account/overview/

[DominicP]

Yes. It says:

Subscription status

Your Spotify Premium subscription will be automatically renewed the 2014-03-23 and charged £9.99 every 1 month, unless you cancel your subscription before that time.