.Net Core 2.0 OIDC注销CORS错误

Question

我们的网络应用基于此示例Integrating Azure AD into an ASP.NET Core web app

应用程序成功登录，没有问题，但是当调用该方法进行注销时，我们在浏览器中看到CORS错误

无法加载https://login.microsoftonline.com/xxx/oauth2/logout?post_logout_redirect_uri=http%3A%2F%2Flocalhost%3A2345%2FAccount%2FSignedOut&state=xxx&x-client-SKU=ID_NET&x-client-ver=2.1.4.0：所请求的资源上不存在“ Access-Control-Allow-Origin”标头。因此，不允许访问来源“ http://localhost:2345”。

并且永远不会调用控制器方法SignedOut（）。

    [HttpGet]
    [EnableCors("default")]
    public IActionResult SignOut()
    {
        // Remove all cache entries for this user and send an OpenID Connect sign-out request.
        string userObjectID = User.FindFirst("http://schemas.microsoft.com/identity/claims/objectidentifier").Value;

        var authContext = new AuthenticationContext(AzureAdOptions.Settings.Authority,
                                                    new NaiveSessionCache(userObjectID, HttpContext.Session));
        authContext.TokenCache.Clear();

        // Let Azure AD sign-out
        var callbackUrl = Url.Action(nameof(SignedOut), "Account", values: null, protocol: Request.Scheme);
        return SignOut(
            new AuthenticationProperties { RedirectUri = callbackUrl },
            CookieAuthenticationDefaults.AuthenticationScheme,
            OpenIdConnectDefaults.AuthenticationScheme);
    }

    [HttpGet]
    [EnableCors("default")]
    public IActionResult SignedOut()
    {
        if (User.Identity.IsAuthenticated)
        {
            // Redirect to home page if the user is authenticated.
            return RedirectToAction(nameof(HomeController.Index), "Home");
        }

        return View();
    }

明确设置CORS以允许任何来源似乎没有帮助

        services.AddCors(options =>
        {
            options.AddPolicy("default",
                    policy => policy
                    .AllowAnyMethod()
                    .AllowAnyOrigin());                        
        });

        app.UseCors("default")

我看不到我在做什么错。