Login to site

I suggest setting up a virtual host locally, for testing.

If you have a URL abc.com/login which redirects to abc.com/admin on success, "/admin" would be an appropriate redirect.
However, if you try to use that locally, as localhost/united/login, then redirecting to "/admin" will redirect to localhost/admin, which does not exist.

I setup virtual hosts for testing all my sites, for instance united.local.
Doing this, united.local/login will redirect to united.local/admin, the intended location.