Have you connected with Sonos support about this? All Sonos does is take your “log in” information, and reach out to the Pandora servers for an authorization token. Then, once you’re authorized, they point you to the Pandora servers to provide you whatever data you have stored there. Sonos doesn’t really keep anything on their side, other than the auth token...

I do understand how this works and yes I spent an hour on chat with sonos.  It turns out that the issue was some interference in the network which required a reboot of all my devices.  At least that is what their tech support implied.  We’ll see if it holds true.  Why there was interference on a network that has not changed an iota in four years is a reasonable question--but then again sonos’ interaction with the wi-fi network via the app appears to be a possible suspect.  Given how frequently this kind of issue appears to occur--not all with Pandora but with other streaming apps as well- I cannot help but wonder if there isn’t more to issue than meets the eye.  In any event--unless or until it occurs again, fixed for now. 

Networks don’t exist in a proverbial vacuum. There are all sorts of outside influences, and even internal changes that we, as consumers, are not really cognizant of. 

i’m pleased it’s working for now, but would encourage a wider perspective.