I am having the same issue. Have 16 Sonos devices - six Play 5's, ten Play 3's and a connect AMP. I keep having to reauthorize Pandora every day. This never happened before until the past two weeks where I have noticed every single day. I reported the issue to Sonos and sent them a diagnostic. My setup is perfect. once I reauthorize Pandora through the Sonos app I am fine. SONOS techs passed the buck to Pandora as they see no issue on their side. I use the free Pandora.
Tanner. I saw this solution posted in the Sonos community forum site and on a follow up it did not address or solve the issue.
Moderator Edit: Changing title for clarity
