UDP for public IP

I have been following Rama’s guide on how to make UDP sockets:A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums
everythings work fine until im using internal ip. The problem starts when i want to switch to public ip , at first i was getting errors when i was trying to make my public ip the endpoint for Receiver but after looking at the source code i realized that EndPoint is only for local ip so i tried with FSocket’s Connect() but with no luck. The socket is getting connected to the IP but receives no data . Could somebody tell me how to setup UDP sockets for external IP.