i have a server with plesk 12.5.30 on Centos 6.7 and use Postfix. If i use webmail i not have a problem bit with client (Outlook Office 2010) i have a problem with smtp. With imap i not have a problem, in smtp i use this:
server: smtp.example.com
door: 25
ssl: TLS
user:
[email protected]...