Out of the blue, my S2 system no longer connects to My Cloud, where all my digital music files are stored. The drive itself is fine and functions independently. When I select My Cloud Home I get an error message telling me the My Cloud account needs to be reauthorized. When I click ‘reauthorize’ it brings up a new screen telling me my account cannot be found. 
Interestingly, when I go the the list of a-z Music Services listed in the system menu My Cloud Home is not there. 
I’ve got used to the seemingly endless full outages with  my cloud services on sonos but according to the website, everything is online.