Asp.net core mvc MVC核心Google外部提供程序登录任务超时

我需要在MVC Core 5中实现Google外部提供程序方面的一些帮助： 我刚刚在我的项目中添加了谷歌外部提供商，一切都很好，但有些事情是错误的！ 以下是我在代码中的操作以及问题描述：

startup.cs :
            services.AddIdentity<User, Role>(config =>
            {
                config.User.RequireUniqueEmail = true;
                config.Password.RequireDigit = true;
                config.Password.RequireLowercase = true;
                config.Password.RequireNonAlphanumeric = false;
                config.Password.RequireUppercase = true;
                config.Password.RequiredLength = 6;
                config.Lockout.AllowedForNewUsers = true;
                config.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(5);
                config.Lockout.MaxFailedAccessAttempts = 3;
            })
                .AddErrorDescriber<CustomIdentityErrorDescriber>()
                .AddEntityFrameworkStores<ApplicationDbContext>()
                .AddDefaultTokenProviders();

            services.AddAuthentication()
                  .AddGoogle("google", opt =>
                  {
                      var googleAuth = _config.GetSection("GoogleExternalSignIn");

                      opt.ClientId = googleAuth["ClientId"];
                      opt.ClientSecret = googleAuth["ClientSecret"];
                      opt.SignInScheme = IdentityConstants.ExternalScheme;
                      //opt.BackchannelTimeout = new TimeSpan(0, 5, 0);
                  })
              ;

我试图设置

opt.BackchannelTimeout=newtimespan（0,5,0）

在AddGoogle配置中，但在尝试登录5分钟后，它返回上述异常。 我怎样才能解决它？ 问题在哪里

System.Threading.CancellationToken.ThrowOperationCanceledException()

TimeoutException: The operation was canceled.
System.Threading.CancellationToken.ThrowOperationCanceledException()

TaskCanceledException: The request was canceled due to the configured HttpClient.Timeout of 300 seconds elapsing.
System.Net.Http.HttpClient.SendAsyncCore(HttpRequestMessage request, HttpCompletionOption completionOption, bool async, bool emitTelemetryStartStop, CancellationToken cancellationToken)

Exception: An error was encountered while handling the remote login.