PO Account Assignment Data is not being updated via IDOC

Hi,

I am using BAPI method to upload POs and the PO gets created successfully with all data supplied in IDOC except data in Account segment. IDOC shows the data correctly in 'Account' and 'AccountX' Segments, however the PO created does not show the Account data under Account Assignment tab and in the EKKN table. Can someone please tell what could be the reason?

Thanks