Plutonium

The answer to your question is in the server creation topic.

Q: Why can't I find my server hosted at home while others can?

A: Your router probably doesn't support NAT-Loopback (aka. NAT-Reflection) and that's why it doesn't know how to forward the network traffic. In order to connect it use your internal IP or 127.0.0.1 if its hosted on the same machine. More information about what NAT-Loopback is and how it works can be found on Wikipedia.

JeanBr8 you need to start the launcher via plutonium.exe (the file you downloaded off our site), launching it via plutonium-launcher-win32.exe will cause the error you're getting.

Thank you so much, you are an angel that God placed on earth.