Not sure if anybody has experienced a similar issue but, as of a couple of months ago, two devices (a mesh wifi and a nest hello) came offline and, despite all efforts, cannot be added back online. Has there been any software updates recently that could be affecting these devices connectivity? I have other unaffected devices connected but, for some reason, these two are the only ones affected.
I tried performing a Factory Reset and removing and adding back both devices. The wifi router came back online for a couple of hours and went back offline. I then unplugged it for more than 1 hour and reconnected ehich seemed to have solved the problem. I didn't have the same results for the doorbell/camera. However, a couple of weeks later (yesterday) I removed it and added it back and it has been online since then. Can't identify what of all the actions performed was the solution but, both devices are working now. Thanks for the recommendations!