Hi,
my Config: Joomla 3.9.23, Sociable 1.1.0, Template Protostar
If the system plugin is active, you cannot go to the registration page and you get the following error message:
500 View class not found : usersViewprofile, /var/www/clients/client1/web4/web/components/com_sociable/views/profile/view.html.php
Regards Tom