There is a new version of this tutorial available for Ubuntu 18.04 (Bionic Beaver).
Postfix Virtual Hosting With LDAP Backend And With Dovecot As IMAP/POP3 Server On Ubuntu Trusty Tahr 14.04 - Page 8
Step 9: Bringing it all together
Issue the following commands to restart all of the services:
service slapd restart
service postfix restart
service dovecot restart
service proftpd stop
service proftpd start
Now you can go to phamm and start adding maildomains and users.
Note: notify me of any errors or problems with this how to so I can improve and amend this how to.