Devices suddenly won’t connect to network

All of the sudden our iPhones, laptops, game systems won’t connect to our network. I have restarted the modem 5 times via the app, as well as just unplugging/replugging….and it says it is online and getting service….but when I try and connect my phone or laptop to it, it says “unable to join, network is unavailable”…thanks for any advice on this, it is making me crazy.