Azure AD B2C Custom Policy with Username Logon - azure-ad-b2c

Question

We have created a custom IEF policy in Azure AD B2C to allow for sign-up and sign-in with username identified local accounts, following the instructions found in Custom B2C Policy for Username based Local Accounts answer. When trying to run the SignUpOrSignIn policy from IEF, it displays the following exception on the logon UI.
AADB2C: An exception has occurred.
After enabling Application Insights logging, we captured the following fatal exception:
Orchestration step '1' of in policy 'B2C_1A_signup_signin of tenant 'xxxxxxxxxx.onmicrosoft.com' specifies more than one enabled validation claims exchange
Orchestration Steps configured as follows:
<UserJourney Id="SignUpOrSignIn">
<OrchestrationSteps>
<OrchestrationStep Order="1" Type="CombinedSignInAndSignUp" ContentDefinitionReferenceId="api.signuporsignin">
<ClaimsProviderSelections>
<ClaimsProviderSelection ValidationClaimsExchangeId="LocalAccountSigninUsernameExchange" />
</ClaimsProviderSelections>
<ClaimsExchanges>
<ClaimsExchange Id="LocalAccountSigninUsernameExchange" TechnicalProfileReferenceId="SelfAsserted-LocalAccountSignin-Username" />
</ClaimsExchanges>
</OrchestrationStep>
<OrchestrationStep Order="2" Type="ClaimsExchange">
<Preconditions>
<Precondition Type="ClaimsExist" ExecuteActionsIf="true">
<Value>objectId</Value>
<Action>SkipThisOrchestrationStep</Action>
</Precondition>
</Preconditions>
<ClaimsExchanges>
<ClaimsExchange Id="SignUpWithLogonUsernameExchange" TechnicalProfileReferenceId="LocalAccountSignUpWithLogonName" />
</ClaimsExchanges>
</OrchestrationStep>
<!-- This step reads any user attributes that we may not have received when in the token. -->
<OrchestrationStep Order="3" Type="ClaimsExchange">
<ClaimsExchanges>
<ClaimsExchange Id="AADUserReadWithObjectId" TechnicalProfileReferenceId="AAD-UserReadUsingObjectId" />
</ClaimsExchanges>
</OrchestrationStep>
<OrchestrationStep Order="4" Type="SendClaims" CpimIssuerTechnicalProfileReferenceId="JwtIssuer" />
</OrchestrationSteps>
<ClientDefinition ReferenceId="DefaultWeb" />
</UserJourney>
Referenced Technical Profile is as follows:
<TechnicalProfile Id="SelfAsserted-LocalAccountSignin-Username">
<DisplayName>Local Account Signin</DisplayName>
<Protocol Name="Proprietary" Handler="Web.TPEngine.Providers.SelfAssertedAttributeProvider, Web.TPEngine, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null" />
<Metadata>
<Item Key="SignUpTarget">SignUpWithLogonUsernameExchange</Item>
<Item Key="setting.operatingMode">Username</Item>
<Item Key="ContentDefinitionReferenceId">api.selfasserted</Item>
</Metadata>
<IncludeInSso>false</IncludeInSso>
<InputClaims>
<InputClaim ClaimTypeReferenceId="signInName" />
</InputClaims>
<OutputClaims>
<OutputClaim ClaimTypeReferenceId="signInName" Required="true" />
<OutputClaim ClaimTypeReferenceId="password" Required="true" />
<OutputClaim ClaimTypeReferenceId="objectId" />
<OutputClaim ClaimTypeReferenceId="authenticationSource" />
</OutputClaims>
<ValidationTechnicalProfiles>
<ValidationTechnicalProfile ReferenceId="login-NonInteractive" />
</ValidationTechnicalProfiles>
<UseTechnicalProfileForSessionManagement ReferenceId="SM-AAD" />
</TechnicalProfile>
We are unable to find any references to this error on google or SO, and can't figure out where there could be multiple enabled validation claims exchanges? The best we can figure, there is some part of the Base configuration that is not being adequately overridden by the extension configuration, and so it sees duplicates?

Answer 1

You are right the base configuration is not being overridden. We did the following to fix.
In TrustFrameworkExtensions.xml
change the id to something else
<UserJouney id="SignUpOrSignInUsername">
...OrchestrationSteps
</UserJourney>
then navigate in SignUpOrSignIn.xml
change referenceid to the what you put in the extenstions.xml
<DefaultUserJourney ReferenceId="SignUpOrSignInUsername" />