Naim App and Atom dropped completely

Very odd over the last 3 weeks the app on my phone and my wife’s phone no longer shows the Atom. Tried a reconnection and worked but then gone back to same situation. Picked up the Qb first generation.
Anyone experienced the same. Searched here and cannot see any threads.
Regards,
Chris.

Try a factory reset of the atom.

I have just noted something - the network the app connects to is different to the one the atom is connected to. That is explained by the fact that I have a router that is the main network name (lets call it MAIN). I have an extended that has the same name with the the extension .ext on it, so MAIN_EXT. The Atom shows network as MAIN and my iPhone to MAIN_EXT. When I changed the latter to MAIN the app shows the Atom. I find this off as the extended has been in the house for years and I have never seen this issue. Maybe a software update has made this more specific or sensitive to a house with extenders.