Dovecot doesn't listen on port 143, 993 in SSL

[남설]

Dear Dovecot Team

First of all, I always appreciated your contribution & effort.
Dovecot is very good tool for me for a while since my 2 years Linux start.

But,
3 days ago, I upgraded my ubuntu 15.04 to 15.10
Then, I realized that my dovecot mail sever didn't work. So I simply 
terminated all the packages and reinstall it.
It means I can't remeber what my previous setting was in my memory.

So, dovecot in run is ver 2.2.18 now.

Dovecot -n shows below and there is no "SSL" option. then all the port 
143, 993 opens(It's not accesible somehow from clients but it's next matter)
----------------------No SSL version------------------------
auth_mechanisms = plain login
mail_location = maildir:~/Maildir
namespace inbox {
   inbox = yes
   location =
   mailbox Drafts {
     special_use = \Drafts
   }
   mailbox Junk {
     special_use = \Junk
   }
   mailbox Sent {
     special_use = \Sent
   }
   mailbox "Sent Messages" {
     special_use = \Sent
   }
   mailbox Trash {
     special_use = \Trash
   }
   prefix =
}
passdb {
   driver = pam
}
protocols = " imap"
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0666
     user = postfix
   }
}
userdb {
   driver = passwd
}
-----------------------------------------------------------
But, If I turn on SSL option with encrypt key and certicate, all port 
143, 993 just disappeared.
I treaded this issue in ubuntu ASK but still no proper answer so far
http://askubuntu.com/questions/722072/dovecot-doesnt-listen-on-993imaps

--------------------------SSL option version----------------
auth_mechanisms = plain login
mail_location = maildir:~/Maildir
namespace inbox {
   inbox = yes
   location =
   mailbox Drafts {
     special_use = \Drafts
   }
   mailbox Junk {
     special_use = \Junk
   }
   mailbox Sent {
     special_use = \Sent
   }
   mailbox "Sent Messages" {
     special_use = \Sent
   }
   mailbox Trash {
     special_use = \Trash
   }
   prefix =
}
passdb {
   driver = pam
}
protocols = " imap"
service auth {
   unix_listener /var/spool/postfix/private/auth {
     group = postfix
     mode = 0666
     user = postfix
   }
}
*ssl_cert = </etc/dovecot/dovecot.csr>**
**ssl_key = </etc/dovecot/private/dovecot.key>*
userdb {
   driver = passwd
}
--------------------------------------------------------------
Looing forward your reply

Thanks in advance