Still stubbornly running 2 Sonos 3s we got in 2012. Pain in the arse sometimes but they do work.
Mine do that every now and then.And system not found this morning
Annoyed is a huge understatement
Mine do that every now and then.
It's annoying but have you tried minimising the app, open another tab then change the tab back to sonos and it should find your stuff again ....