Problem in this FM :SO_NEW_DOCUMENT_ATT_SEND_API1

HI.

I am doing a code for mail sending from ABAP to SOST and SBWP(SAP Inbox).Using the function module is SO_NEW_DOCUMENT_ATT_SEND_API1.mail is sending only for SBWP but it is not received in SOST,could you tell me how to find solution for this.

Thanks.

Regards.

JAY