Hi Yezi,
the Site home option is not enabled if we detect it doesn't have content viewable for the user. If your site home does not have activities, you won't see anything.
We are improving this for the next release, it will display all the information that the Site home displays (like the list of courses, course search, categories) but it will require Moodle 3.2.
What is not clear to me in your message, is that previously that option was displaying something in your site.
Regards, Juan