3418406 - Onboardee user was synched to IAS but login fails - URL User is illegal external user

• You have Identity Authentication Service (IAS) enabled in your SuccessFactors instance: Onboardee users login via IAS is failing although the Onboardee user was synched to IAS.
• Provisioning SSO logs shows "Failed to create external session.@sf_session"

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SAP SuccessFactors HCM Core

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