similar problem here. .
Ever since my upgrade too: f-pbx 12 distro 6.5 on April 10th 2015
I have had numerous 404 errors ,… mostly on two sites=one government ran; and the other
is my web domain host.
Its a little weird because i can still surf the web normally. But on major sites
that may have Apache,Web,MySQL, Php, etc servers running in the background.
They Blotch= 404 error and Even got some weird notice from Google and yahoo
such as
the server is un available “were sorry” we don’t have an answer
I changed my iptables back to what they we’re prior to the upgrade
its only been Min’s but have not had a problem yet.