camera goes poof

I have 6 cameras. During the last hurricane we lost power and after the system came back up. Five cameras came up, one showed dead battery (understandable). BUT one camera removed itself from my system.  This wasn't a "no wifi", "no power" etc. It literally no longer showed up as even being on the system in the app or when I called technical support. And NO I did not remove it. Even if the battery completely died, or all WIFI lost, or it sustained damage (it didn't). Why would it remove the name from the system??