redirection of websites

Hi, our 301 redirection server has been working since the past weeks, just yesterday we've found out that it has not been doing its task in redirecting the sites. Below is part of the config file to redirect a site

server {
server_name <cname address> <users input address i.e: www.sample.com;
rewrite ^/(.*)$ http://<output or redirected address.com>/$1 permanent;
}

The weird thing is, there is another part of config where it passes thru port 88, that one is working.

I've checked my iptables to ensure that port 80 and 88 are both configured and yes both are allowed in iptables.

Tried disabling iptables but same result.

Any other things I need to check on to ensure that this is not a network issue?

Thanks
jepoy