Enable SMTP server requires password and enter a valid Email username and password.
Click Advanced....
In the Advanced Properties window, add the following new entry:
Key = mail.smtp.starttls.enable
Value = true
With these settings, Automation Engine will only be able to send Emails where the "From" Email address is what you have set in the "User Name" field. If you want Automation Engine to be able to send Emails from other Email addresses (i.e. using the "Send Email" task), then the E-mail address set in the "User Name" filed has to be given "Send as" and "Send on behalf" privileges for each of the other Email addresses. Refer to the following link for information on how to do that: https://support.office.com/en-us/article/give-mailbox-permissions-to-another-user-in-office-365-admin-help-1dbcf12f-a9de-4d1d-b0b3-a227f8a736d8