Facebook integration not working in Entra external Id user flow

Question

We have followed the instructions provided in the document [https://learn.microsoft.com/en-us/entra/external-id/customers/how-to-facebook-federation-customers] to integrate with Facebook.
the option to log into with Facebook shows as expected in the login screen. When we try to log in though, the attempt fails with the following error

error Error Domain=MSALErrorDomain Code=-50000 "(null)" UserInfo={MSALErrorDescriptionKey=AADSTS250004:+The+request+failed+with+error:+AADB2C90243:+The+IDP's+client+key/secret+is+not+properly+configured.+Trace+ID:+03a24cf5-ea39-407e-ba7e-bdc6ac4c0400+Correlation+ID:+3ccae658-58e1-4184-b237-4b28b491cad5+Timestamp:+2025-01-31+06:39:34Z, MSALOAuthErrorKey=server_error, MSALCorrelationIDKey=3CCAE658-58E1-4184-B237-4B28B491CAD5, MSALInternalErrorCodeKey=-50006}

We have tried to troubleshoot with the following
1. create new clientid/secret
2. removed and added all the reply URLs all over again
3. published and unpublished our facebook intgration a few times

The app details..
Platform - Android and iOS 
Auth mode - Browser-deligated authentication
MSAL SDK being used for ios v1.6.2 and android v5.8.2

Answer 1

Hello Ankit Yadav,

Thank you for reaching out to Microsoft Q&A. 

We understand that you are facing an error after you have integrated Facebook application integration in Entra external Id user flow. 

The error "aadb2c90243” typically indicates that the IDPs client key/secret is not properly configured. As you have already tried a few steps, here are some additional troubleshooting steps you can check: 

• Please check whether your OAuth redirect URIs are correct or not, also, they should not be expired or invalid, i.e., they should be ‘ https://your-tenant-name.b2clogin.com/your-tenant-name.onmicrosoft.com/oauth2/authresp ’ or ‘ https://your-domain-name/your-tenant-name.onmicrosoft.com/oauth2/authresp ’. There should be no trace of ‘login.microsoftonline.com’ in the redirect URIs in the android version of the app configured for logging into the Microsoft personal accounts. 

Please check the ‘APP ID’ and the corresponding ‘App secret’ created for logging into the Microsoft social accounts through your app page. As it may be conflicting to login with the Microsoft social personal accounts using the Azure AD B2C authentication.  

• Ensure that to make your Facebook application available to Azure AD B2C, select the Status selector at the top right of the page and turn it on to make the Application public, and then select Switch Mode. At this point, the Status should change from Development to Live. 

Sharing relevant documents for more information: https://learn.microsoft.com/en-us/azure/active-directory-b2c/error-codes

https://learn.microsoft.com/en-us/azure/active-directory-b2c/identity-provider-facebook?pivots=b2c-user-flow

Hope this helps. Do let us know if you any further queries.

Thanks & Best Regards

Janaki Kota