The Nest Community is now Google Home & Nest!
We have moved to a new home. Please visit the Google Home & Nest Community to connect with other users, ask questions, and explore the new space.
Google seem to be aware of the issue, and are working on fixes, both for
people who haven't factory reset Chromecast and for those who
have.https://www.googlenestcommunity.com/t5/Streaming/Regarding-an-issue-with-Chromecast-2nd-gen-and-Chromecast-Aud...
Same problem as in this one:
https://www.googlenestcommunity.com/t5/Streaming/We-couldn-t-authenticate/m-p/437872but
since the comments are disabled and the issue hasn't been resolved (the
current accepted answer does not cover my, and I'm sure many ...