I have multiple c by ge bulbs and they all stopped responding a couple weeks ago. They have had this problem before, but it usually fixed itself eventually.
Yesterday I removed one of the bulbs, installed the GE Cync app, and added the bulb to that. The Cync app immediately wanted to update the firmware on the bulb (to 3.7, the bulb was at 3.2). After that, I removed the bulb from Cync, added it back to Google Home and now it works again! I have since done the same with the other bulbs I own and they all work again.
It's a pity the Google Home app can't check the c by ge bulb firmware, especially if it helps with connection issues.
Thanks for posting!
We appreciate you sharing the steps you did. This would be very helpful to other users who are also experiencing the same thing. I also liked your insights about the Home app, and with that, I'd like to encourage you to send a feedback on what are the features that you're looking forward to using the Google Nest speakers.