Apache2, Bind9 doesn't work.

First of all, hello to everybody. I'm new at the forum, I'm writing because I've a big problem. 2 days ago, I've upgraded my vps with ubuntu 14.04 apache 2.4.7, php 5.6 and mysql 5.6 I don't remember the exact package upgraded, sorry. For no reason, since from that day all websites hosted are no working, how if bind9 wasn't working. So I've tried to manage the bad situation, but unfortunately no way out. I re-checked the domains with virtualmin "system settings" -> Re-Check Configuration and the response for all is:

The status of your system is being checked to ensure that all enabled features are available, that the mail server is properly configured, and that quotas are active .. Your system has 3.86 GB of memory, which is at or above the Virtualmin recommended minimum of 256 MB. BIND DNS server is installed, and the system is configured to use it.

Mail server Postfix is installed and configured.

Postfix can support per-domain outgoing IP addresses, but is not currently configured to do so. This can be setup in the Postfix Mailserver module.

Suexec is enabled in the default template, but the Apache module mod_suexec is not installed or not enabled.

Now I've bought the Virtualmin Pro, I would upgrade my vps but I would fix all the problems before.

How can I solve these problems?

Thanks in advance for a reply. Best. Michele