: Ensure your firewall allows the server components. If you aren't on a network, keep the server IP as 127.0.0.1 in the configuration files.

: If you don't want to install heavy software like Visual Studio, look for the Ragnarok-Portable project on rAthena Boards . It uses a portable MSBuild to compile your server files automatically. Ragnarok Battle Offline (The Standalone Game)