Keycloak 26 + Azure AD B2C Integration – “No access_token from server” error

Getting advice
,
1

We are integrating Azure AD B2C with Keycloak (version 26) using OIDC as an external identity provider.

Environment / Configuration details:

  • Keycloak version: 26

  • Azure AD B2C policy: Public client flow (existing application)

  • Client type: Public client

  • Credentials: We are using the same Azure AD B2C application credentials and configuration that are already working for an existing application

  • Integration: Azure AD B2C configured as an OIDC Identity Provider in Keycloak

During user authentication, the login fails and Keycloak logs the following error:

ERROR [org.keycloak.broker.oidc.AbstractOAuth2IdentityProvider]
Failed to make identity provider oauth callback:
org.keycloak.broker.provider.IdentityBrokerException:
No access_token from server. error='null', error_description='null', error_uri='null'
    at org.keycloak.broker.oidc.OIDCIdentityProvider.verifyAccessToken
    at org.keycloak.broker.oidc.OIDCIdentityProvider.getFederatedIdentity
    at org.keycloak.broker.oidc.AbstractOAuth2IdentityProvider$Endpoint.authResponse

This is followed by:

type="IDENTITY_PROVIDER_LOGIN_ERROR"
error="identity_provider_login_failure"

It appears that Keycloak is not receiving an access_token from Azure AD B2C after the OAuth callback, even though the same Azure AD B2C app and policy work correctly for another application.

Has anyone faced this issue with Keycloak 26 and Azure AD B2C, especially when using a public client flow?
Could this be related to:

  • Required scopes (openid, profile, etc.)

  • Response type / response mode

  • Authorization Code vs implicit flow handling in Keycloak 26

  • Azure AD B2C user flow or app registration settings

Any insights or troubleshooting steps would be greatly appreciated.

How to integrate Keycloak 26 with Azure AD B2C
2

It makes no sense to use a public client. Since you are in the context of identity brokering, you must use a confidential client.