ngnix rejects connection to webmail/mail :20000

Hi, I have posted this question in usermin section as well 2 days before.

Can anybody help me?

I am living in VPS world due to virtualmin. A fantastic panel.

I was experimenting to install ngnix on virtualmin and it is working fine. (my box is using CentOS 6.5 64 Bit)

But there is a problem, I am unable to open usermin webmail/mail using :20000.

The browser shows

Google Chrome's connection attempt to ***************** was rejected. The website may be down or your network may not be properly configured.

I have tried to activate usermin/webmail redirection in ngnix but no avail.

Plz anybody help me. Thanks