Plugin deletes page content?

I may be a bit stupid, but this plugin has deleted the content on all pages and replaced it with a login page.

I’ve now taken out the login shortcode, but every page now has the same content and I can’t see any setting that stops that from happening?

Further, if I deactivate the plugin it still takes over pages.

Changing the content on one page changes it on all pages to the same content. This has only been happening since I installed the plugin.

Ultimately, I want the site to be accessible to anyone, but to post they have to register. Can this plugin do that please? If so, how do I stop it taking over all pages?

The page I need help with: [log in to see the link]