How fix error 500 Server Internal Error in post login? - iis

Question

I'm making an application with asp core 2.1 and Vue. My problem is the login to the production server (Windows Server 2012 R2). When I want to do login throws the following error.
Failed to load resource: the server responded with a status of 500 (Internal Server Error)
Access to XMLHttpRequest at 'http://{ip...}/api/account/login' from origin 'http://localhost:8000' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
Uncaught (in promise) TypeError: Cannot set property 'error' of undefined at eval (Login.vue?03db:289)
All other endpoints respond except the login.
However, when I test in the development backend pointing to the production DB, it logs without problems and all the endpoints also respond (get, post etc). As far as I can understand it can be a configuration issue, maybe on the server related to IIS. As I understand if it were a matter of CORS no endpoint would work
public void ConfigureServices(IServiceCollection services)
{
services.AddDbContext<ApplicationDbContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("defaultConnection")));
services.AddIdentity<ApplicationUser, IdentityRole>(options =>
{
options.Password.RequiredLength = 5;
})
.AddEntityFrameworkStores<ApplicationDbContext>()
.AddDefaultTokenProviders();
services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme)
.AddJwtBearer(options =>
options.TokenValidationParameters = new TokenValidationParameters
{
...
});
services.AddTransient<IEmailSender, AuthMessageSender>();
services.AddCors();
//Autorizacion a recursos de la aplicación
services.AddMvc().AddJsonOptions(ConfigureJson);
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
});
}
private void ConfigureJson(MvcJsonOptions obj) {
obj.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, IHostingEnvironment env, ApplicationDbContext context)
{
app.UseAuthentication();
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
else
{
app.UseHsts();
}
app.UseCors(builder => builder
.AllowAnyOrigin()
.AllowAnyMethod()
.AllowAnyHeader()
.AllowCredentials()
);
app.UseDefaultFiles();
app.UseStaticFiles();
app.UseHttpsRedirection();
app.UseMvc();
}
Program.cs
public static IWebHost BuildWebHost(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseKestrel()
.UseContentRoot(Directory.GetCurrentDirectory())
.UseIISIntegration()
.UseStartup<Startup>()
.Build();
}