For smtp email (normally) port:
25 is not SSL
465 is SSL
587 is TLS
That is not to say that your email server that is providing you the ability to send an email hasn't configure 25 to be SSL.
I have a couple of email servers one is authenticated ssl on 465 and the other is Office 365 on 587 with starttls.
With Office 365 (or at least the way my account is configured), I need to set the reply-to equal to the user I logged into otherwise I get an error on sending emails.
V/r,
Gene