Solution for Spotify not working in Sonos

My Sonos-app skipped to next song over and over without playing at all.
Spotify worked fine on all other devices in the same network.
We have not been able to play Spotify for a week through our Sonos-hardware..

This is how I solved our problem:

1. I logged into our router and saw all 4 sonos devices in the mac-lease list.
2. I examined our DHCP-server settings and saw that I had not set any DNS-server, in this scenario the DHCP-server set the router itself as a DNS-server.
3. I changed the DNS-setting to 8.8.8.8 which is the Google DNS on the internet.
4. I deleted all MAC-leases to my four SonosZP, in fact i deleted the whole list, forcing all devices to reconnect.
5. After approx ca 30 seconds all units had connected againand received new MAC leases/ip-numbers. And most important they all got the new DNS-setting 8.8.8.8.
6. Now finally the sonos could connect to spotify and play again.

I interpret this that the sonos app had stored/cached an old ip number to the spotify server. Perhaps Spotify here in Sweden changed the ip of their server a weeks ago?

Perhaps Sonos should add some sort of ping or name lookup service to all added services in the sonos app. If there is no Connection to one of the Music services the could present an error message like "The Music service "Sonos/10.43.212.182" is not answering. Please contact your 3rd party supplier.