For users to be able to send secured emails from SharePoint there are some prerequisites that needs to be met:
1. You need to setup your SEP Server for Global Communication
- Public URL - should be accessible from the Internet.
- SMTP: Hostname, port, username, password needed for registration, password activation/ reset and Global Communication – replying from web.
- Exchange: an account Hostname, Username, Password
- Secured Group – Create and add all users and in the external tab add *@*,Templates – Secure Reply, (in SEP MC: configuration/Web/Secured eMail) Default Web Reply (in SEP MC/policies/yourcompanypolicy/application settings/secured email)
- Certificate - a valid and trusted server certificate that matches the assigned domain name (otherwise your users will get certificate warning)
2. The users that are going to send secured emails from SharePoint needs to be assigned the license: Secured eMail For SharePoint
Please note that if you have automatic license deployment your users will automatically get this license when they Send Secured from SharePoint.