Part of my Yeelight bulbs all of a sudden are offline

I have around 30 Yeelight bulbs in my home. I have used them for a while, however all of a sudden some of my Yeelights are offline.

I have tried to powercycle a number of times , I have tried rebooting my router (Eero Pro mesh routers), but nothing really helps. I probably have half of my bulbs currently offline.

All are updated with latest firmware on my account

Really frustrating and not impressing the family with the choice of predominantly Yeelight bulbs in my home.