Asp.Net Core Challenge returns Null URI Exception error

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

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"
}