To connect through the internet to your own IP usually fails, this is why the localhost connection (127.0.0.1) is a better option.

If you are having more than one PC, and can reacht the other PC over the LAN, there is another thing.
In your router you must not just forward the port, but also direct traffic from and to the IP of the server PC, otherwise the data gets scattered in your LAN.
Change the IP of the server PC to static, and then do not just forward the port but forward it with the internal IP of the server PC.
This way the incoming data gets directed to the server and connection should be possible.

If you have just one PC, either ask a friend to connect or rent a external server.