Domain mapping doesn't have anything to do with activating sites.
The activation link sent in the emails is http://mainsite.com/wp-activate.php?... where mainsite.com is the URL of your main site.
Domain mapping doesn't have anything to do with activating sites.
The activation link sent in the emails is http://mainsite.com/wp-activate.php?... where mainsite.com is the URL of your main site.