Ring intercom offline

My ring intercom suddenly went offline earlier today. I have tried reconnecting but every time I get an error message saying “unable to join the network “Ring Setup f4””. I’ve followed troubleshooting so I have fully charged the battery and done a reset. It keeps flashing blue and red every time I try to connect it. There is no problem with the WiFi strength and the intercom has worked perfectly where it is for months. Any ideas?