==== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.3
- Linux/BSD distribution name and version: Ubuntu 14.04.3 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx):Nginx
- Manage mail accounts with iRedAdmin-Pro? Yes
- Related log if you're reporting an issue: /var/log/fail2ban.log
2016-01-03 17:01:20,249 fail2ban.server : INFO   Changed logging target to /var/log/fail2ban.log for Fail2ban v0.8.11
2016-01-03 17:01:20,250 fail2ban.jail   : INFO   Creating new jail 'ssh'
2016-01-03 17:01:20,326 fail2ban.jail   : INFO   Jail 'ssh' uses pyinotify
2016-01-03 17:01:20,382 fail2ban.jail   : INFO   Initiated 'pyinotify' backend
2016-01-03 17:01:20,387 fail2ban.filter : INFO   Added logfile = /var/log/auth.log
2016-01-03 17:01:20,390 fail2ban.filter : INFO   Set maxRetry = 6
2016-01-03 17:01:20,393 fail2ban.filter : INFO   Set findtime = 600
2016-01-03 17:01:20,394 fail2ban.actions: INFO   Set banTime = 600
2016-01-03 17:01:20,495 fail2ban.jail   : INFO   Jail 'ssh' started
2016-01-03 17:01:21,579 fail2ban.actions: WARNING [ssh] Ban 40.122.126.128
2016-01-03 17:03:57,233 fail2ban.server : INFO   Stopping all jails
2016-01-03 17:03:57,390 fail2ban.actions: WARNING [ssh] Unban 40.122.126.128
2016-01-03 17:03:57,415 fail2ban.actions.action: ERROR  iptables -n -L INPUT | grep -q 'fail2ban-ssh[ \t]' returned 100
2016-01-03 17:03:57,415 fail2ban.actions.action: ERROR  Invariant check failed. Trying to restore a sane environment
2016-01-03 17:03:57,425 fail2ban.actions.action: ERROR  iptables -D INPUT -p tcp -m multiport --dports ssh -j fail2ban-ssh
iptables -F fail2ban-ssh
iptables -X fail2ban-ssh returned 100
2016-01-03 17:03:57,445 fail2ban.actions.action: ERROR  iptables -D fail2ban-ssh -s 40.122.126.128 -j REJECT --reject-with icmp-port-unreachable returned 100
2016-01-03 17:03:57,457 fail2ban.jail   : INFO   Jail 'ssh' stopped
2016-01-03 17:03:57,463 fail2ban.server : INFO   Exiting Fail2ban
====
iptables -S:
-P INPUT DROP
-P FORWARD DROP
-P OUTPUT ACCEPT
-N fail2ban-SOGo
-N fail2ban-default
-N fail2ban-dovecot
-N fail2ban-postfix
-N fail2ban-roundcube
-A INPUT -p tcp -m multiport --dports 80,443,25,587,110,995,143,993,4190 -j fail2ban-SOGo
-A INPUT -p tcp -m multiport --dports 80,443,25,587,110,995,143,993,4190 -j fail2ban-postfix
-A INPUT -p tcp -m multiport --dports 80,443,25,587,110,995,143,993,4190 -j fail2ban-dovecot
-A INPUT -p tcp -m multiport --dports 80,443,25,587,110,995,143,993,4190 -j fail2ban-roundcube
-A INPUT -p tcp -j fail2ban-default
-A INPUT -p tcp -j fail2ban-default
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p icmp -m icmp --icmp-type 8 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 22 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 80 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 443 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 25 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 587 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 110 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 995 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 143 -j ACCEPT
-A INPUT -p tcp -m tcp --dport 993 -j ACCEPT
-A fail2ban-SOGo -j RETURN
-A fail2ban-default -j RETURN
-A fail2ban-default -j RETURN
-A fail2ban-dovecot -j RETURN
-A fail2ban-postfix -j RETURN
-A fail2ban-roundcube -j RETURN

service fail2ban status:
* Status of authentication failure monitor
*  fail2ban is running

Based on the number of repeat sshd failures fail2ban doesn't seem to be doing anything even though status shows it as running. Also, restarting fail2ban does not result in any new log entries.

Any thoughts?

Thanks,
--Bill