Idoc Status error 29 for Out bound Idoc( Receiver of IDoc is its own logic)

I try to create the Out bound Idoc with messag type WMMBXY ( basic Idoc type - WMMBID02 ).

which is configured with the out put type XXXX in VT01N( shippment creation). But I am getting the error status 29 in the Idoc.

Only I am passing the sender, receiver port , partner type and partner function to the communication structure.

Could you please tell me , what is the issue with the partner type configuration .