Job for fail2ban.service failed because the control process exited with error code

I have installed fail2ban on my server (OS: Ubuntu 16.0.4 LTS). When I try to start it, I get the following error message:

Job for fail2ban.service failed because the control process exited with error code.

Here are the outputs for various diagnostic commands:

morpheous@ZEUS:~$ sudo systemctl status fail2ban.service
● fail2ban.service - Fail2Ban Service
   Loaded: loaded (/lib/systemd/system/fail2ban.service; enabled; vendor preset: enabled)
   Active: inactive (dead) (Result: exit-code) since Sat 2016-10-29 11:46:36 UTC; 18s ago
     Docs: man:fail2ban(1)
  Process: 23122 ExecStart=/usr/bin/fail2ban-client -x start (code=exited, status=255)

Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Unit entered failed state.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Failed with result 'exit-code'.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Oct 29 11:46:36 ZEUS systemd[1]: Stopped Fail2Ban Service.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Start request repeated too quickly.
Oct 29 11:46:36 ZEUS systemd[1]: Failed to start Fail2Ban Service.



morpheous@ZEUS:~$ sudo journalctl -xe
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Service hold-off time over, scheduling restart.
Oct 29 11:46:36 ZEUS systemd[1]: Stopped Fail2Ban Service.
-- Subject: Unit fail2ban.service has finished shutting down
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has finished shutting down.
Oct 29 11:46:36 ZEUS systemd[1]: fail2ban.service: Start request repeated too quickly.
Oct 29 11:46:36 ZEUS systemd[1]: Failed to start Fail2Ban Service.
-- Subject: Unit fail2ban.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit fail2ban.service has failed.
-- 
-- The result is failed.
Oct 29 11:46:55 ZEUS sudo[23124]: morpheous : TTY=pts/0 ; PWD=/home/morpheous ; USER=root ; COMMAND=/bin/systemctl status fail2ban.service
Oct 29 11:46:55 ZEUS sudo[23124]: pam_unix(sudo:session): session opened for user root by morpheous(uid=0)
Oct 29 11:46:55 ZEUS sudo[23124]: pam_unix(sudo:session): session closed for user root
Oct 29 11:47:01 ZEUS kernel: iptables_INPUT_denied: IN=eth0 OUT= MAC=[mac_address] SRC=[lan_ip_address] DST=[server_ip_address]
Oct 29 11:47:09 ZEUS sudo[23128]: morpheous : TTY=pts/0 ; PWD=/home/morpheous ; USER=root ; COMMAND=/bin/journalctl -xe
Oct 29 11:47:09 ZEUS sudo[23128]: pam_unix(sudo:session): session opened for user root by morpheous(uid=0)
lines 1353-1374/1374 (END)

Does anyone know what's going on here, and more importantly - how to resolve this issue?