Multi Bench Setup with DNS based multitenancy at Production Server. How To?

Hi, I had tried to implement the same scenario as I asked earlier. What I did till, let me explain and help me out where I’m doing wrong.

So, I had installed ERPNext (production) and created one more bench into a frappe-bench directory by command bench init retail. Now, I came into the retail directory and enabled DNS based multitenancy bench config dns_multitenant on.

Now, I installed bench manager app, and also run bench setup nginx after installing app. Also, reloaded nginx as well. But, I can only see: Sorry! We will be back soon.

What I am missing? Any help !! Is I have to do same as mentioned here: How to setup a production and a development site next to each other - #12 by James_Robertson ?? How to??