Ring Siren doesn't recognise it is hardwired

Had an electrician install the Ring Outdoor Siren, with batteries and hardwired, however the app doesn't recognise that it is hardwired. Have checked that the wires are in the right way. Have not used a Ring Plug-In Adapter (2nd Generation) but a generic adapter that does the same thing. We checked that the voltage/polarity is ok. All help gratefully appreciated. Thanks