Transaction SOST – SAP Connect.
This transaction is usually run by administrators shows all outbound communications from your system using SAPconnect, such as fax or email and their payload/attachments including PDF’s.
For example, it may be commonly used to show the PDF of a payment advice.
Tip – You can configure your email sending SMTP server and port with transaction SCOT (Business Communication Administration). (SCOT–>Settings–>Outbound messages–>SMTP Node)