Multi site Privacy not recognizing privacy settings

I'm trying to create an intranet so users of a subsite can't access content from the main site, but after saving and applying the changes to all the subsites I'm still having the same issue where a subscriber of subsite1 can access to the content of the main site except the dashboard which shows the following message:

But the user can access the content of the main site without any issue, for example this URL

Tried to apply the solution explained here but it didn't work.

Thanks in advance!