About
Network Prevent for Email
and AWS Simple Email Service

Network Prevent for Email
on AWS does not support AWS Simple Email Service (SES) as a downstream Mail Transfer Agent (MTA). It does not work because SES relies on a user name and password credential, while Data Loss Prevention STMP Prevent relies on an anonymous connection.
The next hop (downstream) MTA can be configured either in reflect mode or forward mode. With forward mode, a next hop MTA such as sendmail can be used to forward SMTP traffic.