Cors error in application dotnet core + React web app

Question

I have an application problem that when I send files via POST and the image is larger in Mb Cors error occurs, images of a few kb work normally. Dotnet core api In the api I already added Cors and added permissions in configure services:

services.AddCors(options => options.AddPolicy("CorsPolicy", builder => builder
          .AllowAnyOrigin()
          .AllowAnyMethod()
          .AllowAnyHeader()
          //.AllowCredentials())
          ));

and no configure:

 app.UseCors("CorsPolicy");

Testing via Postman, regardless of image size, no error occurs.

With small image and no error occurs:

With large image and error occurs:

React Code with Axios

api
  .post(`anuncio/${anuncio.idImovel}/imagem`, data, {
    mode: 'cors',
    headers: {
      'content-type': 'multipart/form-data',
      'Access-Control-Allow-Origin':'*',
      authorization: `bearer ${getToken()}`,
    },
    onUploadProgress: (e) => {
      const progress = parseInt(Math.round((e.loaded * 100) / e.total));
      this.updateFile(uploadedFile.id, {
        progress: progress,
      });
    },
  })
  .then((response) => {
    this.updateFile(uploadedFile.id, {
      uploaded: true,
      imagemPrincipal: !principal && index === 0,
      id: response.data.id.toString(),
      href: response.data.link.href,
    });
  })
  .catch(() => {
    this.updateFile(uploadedFile.id, {
      error: true,
      uploaded: true,
    });
  });

};

Environmental data Linux server hosted on AWS. We use NGINX on the frontend. Dotnet core (Kestrel on linux). The upload is done to the S3 of aws (I’ve already set the Cors policies in Bucket).

Answer 1

I believe it is inverted, in the "Configureservices" you add the " services.Addcors();" and in the "Configure" app.Usecors(options => options.Allowanyorigin(). Allowanymethod(). Allowanyheader());

Full example:

  public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDbContext<MeuDbContext>(options =>
                   options.UseSqlServer(
                   Configuration.GetConnectionString("DefaultConnection")));

       
            services.AddCors();
            services.AddSpaStaticFiles(diretorio =>
            {
                diretorio.RootPath = "NomeDoSeuApp";
            });

            services.AddControllers().AddJsonOptions(opcoes =>
            {
                opcoes.JsonSerializerOptions.IgnoreNullValues = true;
            }).AddNewtonsoftJson(opcoes => {
                opcoes.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseCors(opcoes => opcoes.AllowAnyOrigin().AllowAnyMethod().AllowAnyHeader());


            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthorization();

            app.UseStaticFiles();
            app.UseSpaStaticFiles();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });

            app.UseSpa(spa =>
            {
                spa.Options.SourcePath = Path.Combine(Directory.GetCurrentDirectory(), "NomeDoSeuApp");
                if (env.IsDevelopment())
                {
                    spa.UseProxyToSpaDevelopmentServer($"http://localhost:4200/");
                }


            });
        }
    }