BIP security for BIP-BRM invoice integration

Hi,

We are performing BIP-BRM invoice integration using pin_inv_doc_gen utility. For that we have set BI Publisher Security in the BIP security model. But received the below error in bi publisher log

::JOB_PROCESSOR_EXCEPTION::[INSTANCE_ID=TST-OBIP-01.1330596950894] [INSTANCE_JOB_ID=1602]::Error to reestablish global user:: USERNAME=[sadmin] INSTANCE_JOB_ID=[1602::Failed to impersonate user. USERNAME=mylogin INSTANCE_JOB_ID=1602::java.lang.Exception: Failed to impersonate user. USERNAME=sadmin INSTANCE_JOB_ID=1602

Here sadmin is the BIP super user. Please suggest any resolution.