Brainfreeze has been fixed!
Jason from Videostream
To everyone who just encountered the Brainfreeze issue on Chromecast, we've just fixed it. There was an old certificate sitting on the Chromecast TV app that we forgot to replace with the rest of them this week
If you're still seeing the error, try unplugging your Chromecast for a couple seconds and plugging it back in to clear that cache - a big sorry for the inconvenience!