@Bricefa Did you try first the same setup, but without the second deco? It should work. Then you should be able to add the second one.

Yes, it should (and I am pretty sure it will).

@Nirt You should replace your router with the Deco or use different vlans between wired and wireless networks in your existing router if you want to achieve proper isolation. Isolation is performed...

@Nirt Are all your devices behind the Deco? Can you please give some details on your network topology?

@wtf Different IP ranges would not fit the requirement of isolation. This would most probably make it more difficult to reach internal network as users would have to fiddle with network mask, but...

@Nirt It has been said several times, guest network works properly only when deco in router mode. @wtf if your M5 are in AP mode, and you connect through them, it is to be expected that guest network...