Blazor Server available as localhost, but not within local area network. What am i missing?

You'd think this would be easier, no? Your server is only listening on localhost and there are several ways to configure this. The challenge, IMO, is finding out which configuration your server is using.

Here is an article that I found helpful to demystify ASP.NET Core URLS: https://andrewlock.net/5-ways-to-set-the-urls-for-an-aspnetcore-app/

The easiest approach for local testing (but not suitable for prod deployment) is to configure the web host builder in your Program.cs file:

public class Program
{
    public static void Main(string[] args)
    {
        CreateHostBuilder(args).Build().Run();
    }

    public static IHostBuilder CreateHostBuilder(string[] args) =>
        Host.CreateDefaultBuilder(args)
            .ConfigureWebHostDefaults(webBuilder =>
            {
                webBuilder.UseStartup<Startup>();

                // Change here: call UseUrls() with wildcard hostnames
                webBuilder.UseUrls("http://*:5003", "https://*:5004");
            });
}

Once you get your server working (ie, you can access your server from your dev machine via http://127.0.0.1:5003), then you can choose the best configuration option (UseUrls(), environment vars, or command line). Side note: there may be some additional steps to get an HTTPS URL to work, ie, you need to have a trusted (dev) cert.