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It just means you can't access your internal addresses via your external address from an internal address if that makes sense. You need to try accessing your application via a 4G signal, or from elsewhere.
NAT loopback, right I can access the server fine on my internal IP address whilst at home say on my ip, by its internal lp address , so to check if I can access it from out side I needed to use 4 g or maybe BT wifi with fon ?