Cause: Probably WPBakery Page builder (Previously called Visual Composer) is not enabled for your user role. Even WPBakery Page builder plugin is activated, you need to set permission for which roles can access WPBakery Page builder editor.
To do that navigate to WPBakery Bakery Page builder > Role Manager under user roles for example Administrator, choose post types that you want to enable WPBakery Page builder for. It is important to choose for “Pages” in order to edit pages via WPBakery Page builder editor.
FYI: WPBakery Page builder (Previously called Visual Composer) frontend editor is not available with this theme.
If you still can’t edit via WPBakery Page builder feel free to contact us by opening a support ticket.