Hello, @mahlv,
Thanks for choosing and using our theme.
Actually, the issue you are facing is because of the core plugin was not installed correctly.
And your provided Logins are not for Admin, so please share your site WP Admin Login details and the Cpanel or FTP Logins as well in a private content area of this topic and let me know with which page builder you want to import the Demo. With WP Bakery or Elementor?
Regards 8Themes Team.