SAP Message XS846 - Message cannot be processed because Secure E-mail possible by SMTP only

Diagnosis The messsage that you want to encrypt or sign could not be processed inthe SAP system because it was not sent by means of the SMTP node;security functions can only be used if you use the SMTP interface. Procedure Use transaction SCOT to make sure that the recipient of the message isin the address area of the SMTP node.