Need a Multisite (which is subdomain of main site) & need the Network's site to be as sub-d

1) Created Multsite (sub-domain): wordcamp.dev

2) Installed Plugin: https://wordpress.org/plugins/wp-multi-network/

3) Created Network (sub-domain): mumbai.wordcamp.dev

4) Installed Plugin: https://wordpress.org/plugins/wordpress-mu-domain-mapping/

5) Mapped: the sub-site: mumbai.wordcamp.dev

6) Converted the Mutisite to a sub-directory setup (previously: sub-domain)

7) Created a new sub-site under network: mumbai.wordcamp.dev/2016

8) ISSUE: when trying to access mumbai.wordcamp.dev/2016/wp-admin : unable to load, getting 404 error

Still lost!!

SUMMARY: Need a Multisite Network (which is a subdomain of main site) & need the Network’s site to be as a sub-directory.