ASP.NET Core CORS request blocked; why doesn't my API apply the right headers?

Question

Trying to set up CORS with authentication. I have a Web API site up at http://localhost:61000 and a consuming web application up at http://localhost:62000. In the Web API S

Answer 1

In my case the CORS headers were lost because I was making an "application/json" content type request, and in CORS this type of request send first an OPTIONS method, after that, the regular POST is requested. But the OPTIONS was been managed by a Middleware code in my .Net Core pipeline with something like this:

        if (context.Request.Method == "OPTIONS")
        {
            context.Response.StatusCode = (int)HttpStatusCode.OK;
            await context.Response.WriteAsync(string.Empty);
        } 

Once I remove the middleware those requests were flawless attended.