Please double check the configurations on B2C following the steps and try again.

Check Application Registration in Azure Portal

1. Navigate to Azure AD App Registration:

• Go to the Azure portal.
• Open Azure Active Directory > App registrations.
• Select the application you're using for authentication.

2. Verify API Permissions:

• Go to API permissions.
• Ensure your app has the following delegated or application permissions for Microsoft Graph:
  • User.ReadWrite.All (for creating users).
  • Directory.AccessAsUser.All (if needed for elevated directory access).
• If these permissions are missing:
  • Click Add a permission > Microsoft Graph.
  • Add the required permissions.
  • Grant admin consent for the permissions.

3. Expose API (If Needed):

• Go to Expose an API and ensure your API scopes are properly configured.