Why doesn't .NET Core CORS Policy return Access-Control-Allow-Origin response header?-CodePudding

I downloaded the example from dotnet/AspNetCore.Docs github repository. I then opened the CORS .NET 6 project. After I added the missing using statements, I was able to get the project to build. I synchronized the hostname across the project and was able to get it to successfully run and had no issues with CORS. However, when I inspect the response headers, I do not see a Access-Control-Allow-Origin response header as I do with the live example URL.

Why is this? Why is that header missing? I must know as I have an angular application that is plagued with http status 0 when making http calls to the .net Core Backend. The issue is reproducible on an iPhone with Safari.

Here is the code from the example:

builder.Services.AddCors(options =>
{
    options.AddPolicy(name: "MyPolicy",
                policy =>
                {
                    policy.WithOrigins("http://example.com",
                        "http://www.contoso.com",
                        "https://cors1.azurewebsites.net",
                        "https://cors3.azurewebsites.net",
                        "https://localhost:56055",
                        "https://localhost:5001")
                            .WithMethods("PUT", "DELETE", "GET");
                });
});

Note:

You can set any header you want to expose using .WithExposedHeaders("any-custom-header"). You can check here in the official document