I looked into supported/removed sites for the plug-in and see where there was a removed novelupdates.cc-- and I think this may have been in error, because the correct online novel website is a
dot com. It's a website for online novels that have been translated from Chinese/Korean into English, complete with chapter lists.
I've used an extension called Epublifier, but that is not remotely reliable, and fails more often than not, even if I switch from one browser to another. It requires you to hit the button for a pop-up window that lists all the chapter links, then you open the extension. It pulls the links from the pop-up, parses them, and then you can export to epub.
In theory, it's great. In practice, not so much.
I was hoping FFF might be able to help.