Preparing to unpack .../postfix_2.11.3-1ubuntu1_amd64.deb ...
Unpacking postfix (2.11.3-1ubuntu1) ...
Selecting previously unselected package inn.
Preparing to unpack .../inn_1%3a1.7.2q-44build2_amd64.deb ...
Unpacking inn (1:1.7.2q-44build2) ...
Processing triggers for man-db (2.7.0.2-5) ...
Processing triggers for ureadahead (0.100.0-19) ...
ureadahead will be reprofiled on next reboot
Processing triggers for systemd (219-7ubuntu3) ...
Processing triggers for ufw (0.34~rc-0ubuntu5) ...
Setting up postfix (2.11.3-1ubuntu1) ...
Adding group `postfix' (GID 133) ...
Done.
Adding system user `postfix' (UID 121) ...
Adding new user `postfix' (UID 121) with group `postfix' ...
Not creating home directory `/var/spool/postfix'.
Creating /etc/postfix/dynamicmaps.cf
Adding tcp map entry to /etc/postfix/dynamicmaps.cf
Adding sqlite map entry to /etc/postfix/dynamicmaps.cf
Adding group `postdrop' (GID 134) ...
Done.
/etc/aliases does not exist, creating it.

Postfix was not set up.  Start with
  cp /usr/share/postfix/main.cf.debian /etc/postfix/main.cf
.  If you need to make changes, edit
/etc/postfix/main.cf (and others) as needed.  To view Postfix configuration
values, see postconf(1).

After modifying main.cf, be sure to run '/etc/init.d/postfix reload'.

Processing triggers for ufw (0.34~rc-0ubuntu5) ...
Setting up inn (1:1.7.2q-44build2) ...
newaliases: fatal: open /etc/postfix/main.cf: No such file or directory
newaliases command not available.
Job for inn.service failed. See "systemctl status inn.service" and "journalctl -xe" for details.
invoke-rc.d: initscript inn, action "start" failed.
dpkg: error processing package inn (--configure):
 subprocess installed post-installation script returned error exit status 1