ABAP server proxy- parser-item missing error

Dear all,

I am working on File to proxy scenario (ABAP server proxy).

When I executing my scenario, I am getting following error at call adapter pipline step .

< SAP:Category>XIProtocol</SAP:Category>

<SAP:Code area="PARSER">ITEM_MISSING</SAP:Code>

<SAP:P1>Envelope</SAP:P1>

<SAP:Stack>XML element Envelope missing in SOAP message header (SAP XI Extension)</SAP:Stack>

I checked my message payload after message mapping it containing the perfect SOAP Envelop.

What may be the reason for the error?

Regards,

navneet.