Chromecast (2nd gen) and Audio face casting outage

Owners of Chromecast (2nd gen) and Chromecast Audio are currently unable to cast audio or video content. Users are receiving an "Untrusted device" error message, indicating a possible firmware issue. This problem affects all users of these models, with no available workarounds. However, newer Chromecast models are not impacted. The issue appears to be a bug rather than an end-of-life announcement, as Google has not indicated any support changes for these devices. A server-side fix is anticipated.