Deco m5s all working but app says they’re all offline Except for the main one

all firmware is the latest

have tried deleting and setting network up again

have tried deleting and reloading the app 

have tried resetting the main deco

its all working well but the app says they're all off line

i have 13 decos

i have another smaller network of 3 decos that work well (all online) using the same app