Earlier in the day, when reached for comment, a Google spokesperson sent Mashable the following statement: "We're aware of an issue affecting some Google Home and Chromecast users".
Update: Google has a fix ready, and has promised to automatically deploy it within six hours (as of roughly 6PM Eastern).
Experiencing service issues with your Google Home series of devices or Chromecast dongles? If you're also receiving this specific error message, don't bother resetting the speaker like I did because it won't fix anything.
Saying "Ok Google" to a Google Home speaker, for instance, gets the response that "there was a glitch, try again in a few seconds".
As for Chromecast, that's stopped supporting "casting" from apps to the TV adapter.
Have you experienced problems with your Google Home and Chromecast today? Soon after, those with Google Home devices also began reporting that their devices were encountering issues.
The only advice that Google seems to be giving is rebooting its devices by unplugging them from the power source, and plugging them back in two minutes later. "We are really sorry for the inconvenience and are taking steps to prevent this issue from happening in the future".