[Help] I am using the method AcquireTokenByUsernamePassword to get the token, but I get the following error. I haven't configured it properly. thank you

I am using the method AcquireTokenByUsernamePassword to get the token, but I get the following error. I haven’t configured it properly. thank you

Microsoft.Identity.Client：Version=“4.49.1”

code： public readonly static string[] ApiScopes = { “openid”, “profile”, “offline_access”, “User.ManageIdentities.All”, “User.Read.All”,“User.ReadBasic.All”,“User.Invite.All”,“User.ReadWrite.All”,“IdentityProvider.Read.All” };

app = PublicClientApplicationBuilder.Create(ClientId) .WithB2CAuthority(AuthoritySignUpSignIn) .WithRedirectUri(“http://localhost:8080/home”) .WithExtraQueryParameters(new Dictionary<string, string>() { { “nonce”, Guid.NewGuid().ToString() } }) .WithLogging(Log, LogLevel.Info, false) .Build();

authResult = await app.AcquireTokenByUsernamePassword(App.ApiScopes, “UserName”, “UserPassword”).ExecuteAsync();

Error Message： Error Acquiring Token: Microsoft.Identity.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path ‘’, line 0, position 0. at Microsoft.Identity.Json.JsonTextReader.ParseValue() at Microsoft.Identity.Json.JsonReader.ReadForType(JsonContract contract, Boolean hasConverter) at Microsoft.Identity.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Microsoft.Identity.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) at Microsoft.Identity.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings) at Microsoft.Identity.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings) at Microsoft.Identity.Client.Utils.JsonHelper.DeserializeFromJson[T](String json) at Microsoft.Identity.Client.OAuth2.OAuth2Client.CreateResponse[T](HttpResponse response, RequestContext requestContext) at Microsoft.Identity.Client.OAuth2.OAuth2Client.ExecuteRequestAsync[T](Uri endPoint, HttpMethod method, RequestContext requestContext, Boolean expectErrorsOn200OK, Boolean addCommonHeaders, Func2 onBeforePostRequestData) at Microsoft.Identity.Client.OAuth2.OAuth2Client.GetTokenAsync(Uri endPoint, RequestContext requestContext, Boolean addCommonHeaders, Func2 onBeforePostRequestHandler) at Microsoft.Identity.Client.OAuth2.TokenClient.SendHttpAndClearTelemetryAsync(String tokenEndpoint, ILoggerAdapter logger) at Microsoft.Identity.Client.OAuth2.TokenClient.SendTokenRequestAsync(IDictionary`2 additionalBodyParameters, String scopeOverride, String tokenEndpointOverride, CancellationToken cancellationToken) at Microsoft.Identity.Client.Internal.Requests.UsernamePasswordRequest.GetTokenResponseAsync(CancellationToken cancellationToken) at Microsoft.Identity.Client.Internal.Requests.UsernamePasswordRequest.ExecuteAsync(CancellationToken cancellationToken) at Microsoft.Identity.Client.Internal.Requests.RequestBase.RunAsync(CancellationToken cancellationToken) at Microsoft.Identity.Client.ApiConfig.Executors.PublicClientExecutor.ExecuteAsync(AcquireTokenCommonParameters commonParameters, AcquireTokenByUsernamePasswordParameters usernamePasswordParameters, CancellationToken cancellationToken)

[bgavrilMS]

Still, one can argue that MSAL should throw a friendlier exception and not a JSON parsing error. I would recommend treating this as a bug.

@kou-h - a few thoughts:

1. You can’t ask for Graph scopes with a B2C user. Graph only works with Azure AD authority
2. Username / Password is insecure because apps should not handle passwowrds. But apart from that, the flow will not work with MFA. So please use AcquireTokenInteractive instead.
3. Can you capture a network trace and send it over? Use bogavril at microsoft.com

[bgavrilMS]

@SameerK-MSFT - not sure why this matters? It’s just about throwing a better exception if folks attempt ROPC with B2C authority and graph scope.