Saving outgoing notifications in Messaging Application Programming Interface (MAPI) is available only for on-premises deployments.
If you use the MAPI email protocol and you want to save messages on the Exchange server, you must configure your outgoing mailbox to save outgoing notification emails in an Outlook folder. To save outgoing notifications, add the following line to the EmailDaemon.properties file:
ARSystemServer.MAPI_Sent_Folder=folderName
ARSystemServer is the name of the AR System server associated with the Email Engine, folderName is the name of the folder that stores the outgoing notification emails. For example, enter Sent Items to save messages to your Sent Items folder in Microsoft Outlook.