I’m getting this error when trying to access anything from Amazon Music. I’ve authorised the account fine, and it lists everything from Amazon fine - playlists, stations, songs, etc, but as soon as I try to play something I get this error. 
My Sonos account was originally created when I lived in the UK, but I live back in Australia now. My Amazon account is .com.au, not .co.uk. I’ve never tried to connect Sonos to Amazon.co.uk before.