No 'Access-Control-Allow-Origin' header is present on the requested resource, using ReactJS with NetCore. How to make AllowAnyOrigin work

Question

Im using ReactJS and Net Core as backend. As soon as I put up a request via to my Net Core, I was responded with a message http://localhost:8080/auth/someendpoint' from origin 'http://localhost:5173' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

I've set my Startup.cs:

//Add CORS
        //for development env
        services.AddCors(options =>
        {
            options.AddPolicy("AllowAnyOrigin",
                builder => builder
                    .AllowAnyOrigin()
                    .AllowAnyMethod()
                    .AllowAnyHeader());
        });

and use it like:

app.UseCors("AllowAnyOrigin");

Answer 1

Update: finally fixed it, seems like this happens because im trying to use a custom header on my request, i deleted it and it works