In SRM PO is not transferred to the backend system correctly because of the backend error .
How could we find the error messages and start trouble shooting ?
1, In SRM 700 system , there is new function called "BACKEND CHECK"
Consistency Check Active in Back-End
If the indicator is set, a consistency check is carried out before the purchase order is replicated from SAP SRM to SAP ERP. The consistency check simulates the replication. Appropriate error or warning messages are output if problems are detected during the check.
If the indicator is not set, the purchase order is replicated from SAP SRM to SAP ERP. It is also transmitted to the supplier, even if problems occur during replication to SAP ERP.
Back-End Messages Displayed as Errors
If the indicator is set, all messages output by the SAP ERP back-end after the consistency check are displayed in SAP SRM as error messages. These errors then need to be corrected before the purchase order is transmitted to the supplier.
If the indicator is not set, these messages are displayed as warning messages in SAP SRM. The purchase order is replicated to SAP ERP and transmitted to the supplier even if the problems are not corrected.
Example about the Backend Errors when creating a PO :
When the Backend error is checked, SRM calls META_DPO_TRANSFER. Where BBP_PO_INBOUND is called. If you are creating the PO, the backend function module BAPI_PO_CREATE1 is called by RFC with a flag "TESTRUN". If you check the return table, you will have a list of backend warning or errors .
2, If you are in SRM 550 system, Please see the details in blog:
The suggestion could also be used in other situation if the BAPI_PO_CREATE1 or BAPI_PO_CHANGE is called , like Shopping cart backend error in classic scenario.