Apple changed some things regarding WiFi with iOS 13. If you want to use CNCopyCurrentNetworkInfo your app needs to have one of the following
I had same issue from iOS 13.0 but it seems that apple fixed in 13.3 The requirement in the doc that it should be either a network added by the app or that location should be enabled or that app had an active VPN did not work for 13.1 13.1 13.2