So Based on the previous forum result I finally implemented multi-domain and domain mapping in my main site. Only difference is I installed the latest version as supposed to the version I had tested.
The issue is
I have two dns names mapped to an ip
site1 and site2.
created multi-domains and have a new blog site2/site
then navigated to site2/site/wp-admin - Tools-Domain Mapping
Mapped Site2 - Site2/site
But when I navigate to Site2 it takes me to the main site (site1)