Asp.Net Core Challenge returns Null URI Exception

Question

I am creating an ASP.NET core web API and want to integrate microsoft Azure AD authentication services. On compile-time everything works just fine. However, when I access the route meant to return a Challenge, I get a null URI Exception (Stacktrace below). I have tried specifying a challenge URI in my ConfigureServices:

 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();

        }

I have also tried changing the redirect URI in my route:

    [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);
        }


    }
}

I cant seem to find the root of the issue, and the stacktrace makes no sense to me:

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, Scope& scope, Object& state, 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()

I am using ASP.NET Core 2.1.1 with MVC, Cors, Azure AD, and EntityFramework There is no in-project CSHTML, as we are using a separate front end (Using VueJS)

Answer 1

In all likelihood you need to set the URI.

There are three things I suggest you check:

1. Have you added your database endpoint and key to the config file? It looks like the issue might be with your connection strings. Add the keys within the app settings of your config file if you have not done so already. Ensure that your app settings are there and any web service URLs are being referenced properly.
2. Do a null check on the URI to ensure that a null value does not get passed in.
3. Check the system logs on your app server.
4. Ensure that you are passing in all necessary parameters.
5. Register the app to a new application pool.

Hope this helps!

Answer 2

I think the problem is because the Instance property is not set on your AzureADOptions

See this link

https://github.com/aspnet/AADIntegration/issues/34

So add, for example

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