Add Cors Dotnet core

Startup.cs

public class Startup
{
    
    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddTransient<MyActionFilter>();
        
        
        services.AddControllers(options => 
        /// ...
        
        ervices.AddCors(options =>
            {
                var frontendUrl = Configuration.GetValue<string>("frontend_url");
                options.AddDefaultPolicy(builder =>
                {
                    builder
                        .WithOrigins(frontendUrl)
                        .AllowAnyMethod()
                        .AllowAnyHeader();
                });
            });

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

        app.UseRouting();

        app.UseCors();

      }

}