Added better error message for OIDC error

src/client/Microsoft.Identity.Client/Internal/Constants.cs

@@ -28,6 +28,9 @@ internal static class Constants
 
         public const string CcsRoutingHintHeader = "x-anchormailbox";
         public const string AadThrottledErrorCode = "AADSTS50196";
+        public const string AadAccountTypeAndResourceIncompatibleErrorCode = "AADSTS500207";
+        public const string AadMissingScopeErrorCode = "AADSTS900144";
+
         //Represents 5 minutes in Unit time stamp
         public const int DefaultJitterRangeInSeconds = 300;
         public static readonly TimeSpan AccessTokenExpirationBuffer = TimeSpan.FromMinutes(5);

src/client/Microsoft.Identity.Client/MsalErrorMessage.cs

@@ -444,5 +444,6 @@ public static string InvalidTokenProviderResponseValue(string invalidValueName)
         public const string RegionRequiredForMtlsPopMessage = "Regional auto-detect failed. mTLS Proof-of-Possession requires a region to be specified, as there is no global endpoint for mTLS. See https://aka.ms/msal-net-pop for details.";
         public const string ForceRefreshAndTokenHasNotCompatible = "Cannot specify ForceRefresh and AccessTokenSha256ToRefresh in the same request.";
         public const string RequestTimeOut = "Request to the endpoint timed out.";
+        public const string MalformedOidcAuthorityFormat = "Possible cause: When using Entra External ID, you didn't append /v2.0, for example {0}/v2.0\"";
     }
 }

src/client/Microsoft.Identity.Client/MsalServiceExceptionFactory.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Net;
 using System.Text;
 using Microsoft.Identity.Client.Http;
@@ -41,7 +42,7 @@ internal static MsalServiceException FromHttpResponse(
                 }
                 else  
                 {  
-                    errorMessageToUse  = errorMessage;  
+                    errorMessageToUse = errorMessage;  
                 }
 
                 if (oAuth2Response.Claims == null)
@@ -64,6 +65,13 @@ internal static MsalServiceException FromHttpResponse(
                     innerException);
             }
 
+            var authorityInfo = context?.ServiceBundle.Config.Authority.AuthorityInfo;
+
+            if (IsOidcAuthorityError(authorityInfo, oAuth2Response?.ErrorDescription))
+            {
+                errorMessage += " " +  string.Format(CultureInfo.InvariantCulture, MsalErrorMessage.MalformedOidcAuthorityFormat, $"{authorityInfo.CanonicalAuthority}");
+            }
+
             ex ??= new MsalServiceException(errorCode, GetErrorMessage(errorMessage, httpResponse, context), innerException);
 
             SetHttpExceptionData(ex, httpResponse);
@@ -108,6 +116,16 @@ private static bool IsThrottled(OAuth2ResponseBase oAuth2Response)
                oAuth2Response.ErrorDescription.StartsWith(Constants.AadThrottledErrorCode);
         }
 
+        private static bool IsOidcAuthorityError(AuthorityInfo authortyInfo, string ErrorDescription)
+        {
+            return authortyInfo is not null &&
+                authortyInfo.AuthorityType == AuthorityType.Generic && // Generic Oidc authority
+                !authortyInfo.CanonicalAuthority!.AbsoluteUri.EndsWith("/v2.0") && // Does not end with /v2.0
+                ErrorDescription != null &&
+                (ErrorDescription.StartsWith(Constants.AadAccountTypeAndResourceIncompatibleErrorCode) || // Certain error codes are returned
+                ErrorDescription.StartsWith(Constants.AadMissingScopeErrorCode));
+        }
+
         internal static MsalServiceException FromBrokerResponse(
           MsalTokenResponse msalTokenResponse,
           string errorMessage)

src/client/Microsoft.Identity.Client/OAuth2/OAuth2Client.cs

@@ -259,7 +259,7 @@ private static void ThrowServerException(HttpResponse response, RequestContext r
             MsalServiceException exceptionToThrow;
             try
             {
-                exceptionToThrow = ExtractErrorsFromTheResponse(response, ref shouldLogAsError);
+                exceptionToThrow = ExtractErrorsFromTheResponse(response, ref shouldLogAsError, requestContext);
             }
             catch (JsonException) // in the rare case we get an error response we cannot deserialize
             {
@@ -309,7 +309,7 @@ private static void ThrowServerException(HttpResponse response, RequestContext r
             throw exceptionToThrow;
         }
 
-        private static MsalServiceException ExtractErrorsFromTheResponse(HttpResponse response, ref bool shouldLogAsError)
+        private static MsalServiceException ExtractErrorsFromTheResponse(HttpResponse response, ref bool shouldLogAsError, RequestContext context = null)
         {
             // In cases where the end-point is not found (404) response.body will be empty.
             if (string.IsNullOrWhiteSpace(response.Body))
@@ -352,7 +352,8 @@ private static MsalServiceException ExtractErrorsFromTheResponse(HttpResponse re
             return MsalServiceExceptionFactory.FromHttpResponse(
                 msalTokenResponse.Error,
                 msalTokenResponse.ErrorDescription,
-                response);
+                response,
+                context: context);
         }
 
         private Uri AddExtraQueryParams(Uri endPoint)

tests/Microsoft.Identity.Test.Common/Core/Mocks/MockHelpers.cs

@@ -260,9 +260,10 @@ public static HttpResponseMessage CreateFailureTokenResponseMessage(
             string error,
             string subError = null,
             string correlationId = null,
-            HttpStatusCode? customStatusCode = null)
+            HttpStatusCode? customStatusCode = null,
+            string errorCode = "AADSTS00000")
         {
-            string message = "{\"error\":\"" + error + "\",\"error_description\":\"AADSTS00000: Error for test." +
+            string message = "{\"error\":\"" + error + "\",\"error_description\":\"" + errorCode + ": Error for test." +
                 "Trace ID: f7ec686c-9196-4220-a754-cd9197de44e9Correlation ID: " +
                 "04bb0cae-580b-49ac-9a10-b6c3316b1eaaTimestamp: 2015-09-16 07:24:55Z\"," +
                 "\"error_codes\":[70002,70008],\"timestamp\":\"2015-09-16 07:24:55Z\"," +

tests/Microsoft.Identity.Test.Common/Core/Mocks/MockHttpManagerExtensions.cs

@@ -87,15 +87,18 @@ public static MockHttpMessageHandler AddFailureTokenEndpointResponse(
            this MockHttpManager httpManager,
            string error,
            string authority = TestConstants.AuthorityCommonTenant, 
-           string correlationId = null)
+           string correlationId = null,
+           string AadErrorCode = "AADSTS00000",
+           string expectedUrl = null)
         {
             var handler = new MockHttpMessageHandler()
             {
-                ExpectedUrl = authority + "oauth2/v2.0/token",
+                ExpectedUrl = expectedUrl != null? expectedUrl : $"{authority}oauth2/v2.0/token",
                 ExpectedMethod = HttpMethod.Post,
                 ResponseMessage = MockHelpers.CreateFailureTokenResponseMessage(
-                    error, 
-                    correlationId: correlationId)
+                    error,
+                    correlationId: correlationId,
+                    errorCode: AadErrorCode)
             };
             httpManager.AddMockHandler(handler);
             return handler;

tests/Microsoft.Identity.Test.Common/TestConstants.cs

@@ -122,6 +122,8 @@ public static HashSet<string> s_scope
         public const string CiamAuthorityMainFormat = "https://tenant.ciamlogin.com/";
         public const string CiamAuthorityWithFriendlyName = "https://tenant.ciamlogin.com/tenant.onmicrosoft.com";
         public const string CiamAuthorityWithGuid = "https://tenant.ciamlogin.com/aaaaaaab-aaaa-aaaa-cccc-aaaaaaaaaaaa";
+        public const string CiamCUDAuthority = "https://login.msidlabsciam.com/aaaaaaab-aaaa-aaaa-cccc-aaaaaaaaaaaa/v2.0";
+        public const string CiamCUDAuthorityMalformed = "https://login.msidlabsciam.com/aaaaaaab-aaaa-aaaa-cccc-aaaaaaaaaaaa";
 
         public const string B2CLoginGlobal = ".b2clogin.com";
         public const string B2CLoginUSGov = ".b2clogin.us";
@@ -540,6 +542,14 @@ public static MsalTokenResponse CreateMsalTokenResponseWithTokenSource()
    ],
    ""backchannel_user_code_parameter_supported"":true
 }";
+        public static string GetOidcResponse(string authority = null)
+        {
+            if (string.IsNullOrEmpty(authority))
+            {
+                return GenericOidcResponse;
+            }
+            return GenericOidcResponse.Replace("https://demo.duendesoftware.com", authority.TrimEnd('/'));
+        }
 
         public static MsalTokenResponse CreateAadTestTokenResponse()
         {

tests/Microsoft.Identity.Test.Unit/CoreTests/InstanceTests/GenericAuthorityTests.cs

@@ -6,6 +6,7 @@
 using System.Diagnostics;
 using System.Globalization;
 using System.Linq;
+using System.Net;
 using System.Net.Http;
 using System.Threading;
 using System.Threading.Tasks;
@@ -333,6 +334,60 @@ public async Task BadOidcResponse_ThrowsException_Async(string badOidcResponseTy
             }
         }
 
+        [TestMethod]
+        public async Task Oidc_Malformed_Failure_Async()
+        {
+            using (var httpManager = new MockHttpManager())
+            {
+                string authority = TestConstants.CiamCUDAuthorityMalformed;
+                IConfidentialClientApplication app = ConfidentialClientApplicationBuilder
+                    .Create(TestConstants.ClientId)
+                    .WithHttpManager(httpManager)
+                    .WithOidcAuthority(authority)
+                    .WithClientSecret(TestConstants.ClientSecret)
+                    .Build();
+
+                httpManager.AddMockHandler(
+                    CreateOidcHttpHandler($"{authority}/{Constants.WellKnownOpenIdConfigurationPath}", authority));
+
+                httpManager.AddFailureTokenEndpointResponse(
+                                error: "error",
+                                AadErrorCode: Constants.AadAccountTypeAndResourceIncompatibleErrorCode,
+                                expectedUrl: $"{TestConstants.CiamCUDAuthorityMalformed}/connect/token");
+
+                Assert.AreEqual(authority, app.Authority);
+                var confidentailClientApp = (ConfidentialClientApplication)app;
+                Assert.AreEqual(AuthorityType.Generic, confidentailClientApp.AuthorityInfo.AuthorityType);
+
+                var ex = await AssertException.TaskThrowsAsync<MsalServiceException>(() =>
+                         app.AcquireTokenForClient(new[] { "api" })
+                             .ExecuteAsync())
+                             .ConfigureAwait(false);
+
+                Assert.IsTrue(ex.Message.Contains(
+                                string.Format(
+                                    CultureInfo.InvariantCulture, 
+                                    MsalErrorMessage.MalformedOidcAuthorityFormat, 
+                                    TestConstants.CiamCUDAuthorityMalformed)));
+
+                httpManager.AddFailureTokenEndpointResponse(
+                error: "error",
+                AadErrorCode: Constants.AadMissingScopeErrorCode,
+                expectedUrl: $"{TestConstants.CiamCUDAuthorityMalformed}/connect/token");
+
+                ex = await AssertException.TaskThrowsAsync<MsalServiceException>(() =>
+                         app.AcquireTokenForClient(new[] { "api" })
+                             .ExecuteAsync())
+                             .ConfigureAwait(false);
+
+                Assert.IsTrue(ex.Message.Contains(
+                                string.Format(
+                                    CultureInfo.InvariantCulture,
+                                    MsalErrorMessage.MalformedOidcAuthorityFormat,
+                                    TestConstants.CiamCUDAuthorityMalformed)));
+            }
+        }
+
         [TestMethod]
         public async Task OidcIssuerValidation_AcceptsDifferentPath_Async()
         {
@@ -479,13 +534,13 @@ private static string CreateIdToken()
             return string.Format(CultureInfo.InvariantCulture, "someheader.{0}.somesignature", Base64UrlHelpers.Encode(id));
         }
 
-        private static MockHttpMessageHandler CreateOidcHttpHandler(string oidcEndpoint)
+        private static MockHttpMessageHandler CreateOidcHttpHandler(string oidcEndpoint, string authority = null)
         {
             return new MockHttpMessageHandler()
             {
                 ExpectedMethod = HttpMethod.Get,
                 ExpectedUrl = oidcEndpoint,
-                ResponseMessage = MockHelpers.CreateSuccessResponseMessage(TestConstants.GenericOidcResponse)
+                ResponseMessage = MockHelpers.CreateSuccessResponseMessage(TestConstants.GetOidcResponse(authority))
             };
         }
     }