Prevent Display Of Members To Visitors Not Registered & Logged In
How do we prevent access to the members list for site visitors that are not registered or logged in?
Please navigate to the Dashboard> Forums > Usergroups, edit the Guest usergropup and uncheck "Can View Members" and "Can View Profiles" CANs/permissions. See the screenshot below:
In any case please don't forget to delete all caches and press CTRL+F5(twice) on the frontend before checking.