SAP ECC6 Purchase Order to SAP B1 Sales Order EDI solution

Hi

We are in the process of implementing EDI solution between ECC6 and SAP Business One 8.82 PL11B1if Version : 1.16.0

ECC6 is Customer

SAP Business One is Supplier

From SAP B1 we are able to send A/R Invoices IDOC and ECC6 receives these invoices.

Error:

While sending IDOC Purchase Orders from ECC6 to SAP B1 there is and error in ECC6 : Function IDOC_INBOUND_ASYNCHRONOUS is not available

Attached print screen for reference

Could you please suggest the reason for this error.

We have tried various ways in terms of set-up / configuration.

Regards

Rajarshi