All Is Not Lost If You Have
Second generation Chromecast and Chromecast Audio devices ran into a wee bit of a problem yesterday. When owners of the devices tried to use them to stream content they were greeted with an untrusted device error, which prevented their use. At least some Chromecast owners tried the old standby, a factory reset, only to find the problem remained; or became even worse. This is because Google failed to renew an intermediate CA expire which expired after 10 years, specifically on March 9th. That broke the trust chain between Google and your Chromecast, and prevents you from streaming anything.
Google told Ars Technica they do intend to fix this issue, the renewal of the CA is simple but trying to automagically revive those Chromecasts which have been factory reset may be a bit more of a challenge. If you are impatient to get back to your shows, there is a possible fix you can try though it is unofficial and could cause more pain for you.
If you want to give it a shot you can find the process described here, but do so at your own risk.
