Redirect-loops in child networks with subdomain setup, using Nginx

I’m stuck in attempting to use Wp Multi Network plugin. I’d great appreciate some help/guidance. Below are relevant details I could think of:

Setup

1. Main network: Multisite with subdomains setup
2. In wp-config.php I commented out the following lines

   //define('DOMAIN_CURRENT_SITE', 'rooshia.com');
   //define('PATH_CURRENT_SITE', '/');
   //define('SITE_ID_CURRENT_SITE', 1);
   //define('BLOG_ID_CURRENT_SITE', 1);

3. I Use Nginx and here is my set up>> http://pastebin.com/2HYe7T8D

I tested two child networks
1st child nework uses own domain name; with A record pointing to the same IP address as the main network

Network set up:

Domain: childnework.com
Path: /

Issues

• Logging in on the main network is not recognized by a child network and vise versa. I must log in every network as if they’re separate installs
• I can access child network’s blog admin; i.e childnetwork.com/wp-admin/, front page: e.g childnetwork.com and its blog posts; e.g childnetwork.com/sample-page/ and post new articles. However, attempting to access child network admin, childnetwork.com/wp-admin/network/ results in a redirect-loop
• From networks listing, network admin link of a child nework has double slashes; i.e http://childnetwork.com//wp-admin/network/

2nd child nework: using a subdomain
Network set up:

Domain: childnework2.mainnework.com
Path: /

Issues
All URLs, admin and front page, have redirect loop; all of them redirect to http://childnetwork2.mainnetwork.com/wp-signup.php?new=childnetwork2.mainnetwork.com

Suggestions tried that didn’t work in both set ups:

• Clearing cookies
• Changing Authentication Unique Keys and Salts in wp-config.php
• Tried both with & without define( ‘DOMAIN_CURRENT_SITE’, $_SERVER[‘SERVER_NAME’] ); in wp-config.php

https://wordpress.org/plugins/wp-multi-network/