c# – Asp.Net核心挑战返回Null URI异常错误

我正在创建一个ASP.NET核心Web API,并希望集成Microsoft Azure AD身份验证服务.在编译时,一切正常.但是,当我访问要返回Challenge的路由时,我得到一个空URI异常(下面的Stacktrace).我已经尝试在我的ConfigureServices中指定挑战URI：

public void ConfigureServices(IServiceCollection services)
        {

            services.AddDbContext<AppContext>(options => options.UseSqlite("Data Source=app.db"));

            // Identity/Authorization Services
            services.AddAuthentication(sharedOptions =>
                {
                    sharedOptions.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
                    sharedOptions.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
                })
                .AddAzureAD(options =>
                {
                    options.ClientId = Configuration["Authentication:Microsoft:ApplicationId"];
                    options.ClientSecret = Configuration["Authentication:Microsoft:Password"];
                    options.SignedOutCallbackPath = "/api/v1/accounts/signout";
                })
                .AddCookie(options => options.AccessDeniedPath = "/api/v1/accounts/accessdenied");

            services.AddTransient<IRecognitionService,RecognitionService>();
            services.AddTransient<IProfileService,ProfileService>();


            services.AddMvc();

        }

我也尝试在路由中更改重定向URI：

[Route("api/v1/accounts/[action]")]
    public class AccountController : Controller
    {
        public async Task<IActionResult> AccessDenied()
        {
            return Unauthorized();
        }

        [HttpGet]
        public async Task<IActionResult> Signin()
        {
            return Challenge(new AuthenticationProperties {RedirectUri = "/accessdenied"},AzureADDefaults.AuthenticationScheme);
        }


    }
}

我似乎无法找到问题的根源,而堆栈跟踪对我来说毫无意义：

System.ArgumentNullException: Value cannot be null.
Parameter name: uriString
   at System.Uri..ctor(String uriString)
   at Microsoft.AspNetCore.Authentication.AzureAD.UI.OpenIdConnectOptionsConfiguration.Configure(String name,OpenIdConnectOptions options)
   at Microsoft.Extensions.Options.OptionsFactory`1.Create(String name)
   at System.Lazy`1.CreateValue()
   at System.Lazy`1.LazyInitValue()
   at Microsoft.AspNetCore.Authentication.AuthenticationHandler`1.<InitializeAsync>d__42.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Authentication.AuthenticationHandlerProvider.<GetHandlerAsync>d__5.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Authentication.AuthenticationService.<ChallengeAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Authentication.AuthenticationHandler`1.<ChallengeAsync>d__54.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Authentication.AuthenticationService.<ChallengeAsync>d__11.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.ChallengeResult.<ExecuteResultAsync>d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeResultAsync>d__20.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeNextResultFilterAsync>d__28`2.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResultExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.ResultNext[TFilter,TFilterAsync](State& next,Scope& scope,Object& state,Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeResultFilters>d__26.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeNextResourceFilter>d__23.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next,Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeFilterPipelineAsync>d__18.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.<InvokeAsync>d__16.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Builder.RouterMiddleware.<Invoke>d__4.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.<Invoke>d__7.MoveNext()

我正在使用ASP.NET Core 2.1.1与MVC,Cors,Azure AD和EntityFramework
没有项目内的CSHTML,因为我们使用单独的前端(使用VueJS)

.AddAzureAD(options => 
{
  options.Instance = "https://login.microsoftonline.com"
}