Hi @Faisal Rashid , Thanks for reaching out.
On Behalf of flow is suitable for chained Web APIs where one API need to calls another downstream Web API.
Although Azure AD B2C doesn't support On Behalf of flow, so we can't utilize its token to call another downstream API.
However, On-Behalf-Of works for applications registered in Microsoft Entra ID, it does not work for applications registered in Azure AD B2C, regardless of the tenant (Microsoft Entra ID or Azure AD B2C) that is issuing the tokens.
Hope this will help.
Thanks,
Shweta
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