Cover generator not working

[josieg]

Description

The cover generator doesn't seem to be working in any of the themes. There is an error message on the page that reads: "Some dependencies for Cover Generator exports could not be found. Please verify that you have completed the installation instructions."

And the buttons used to generate a cover cannot be clicked.

Expected behaviour

I add the information that I want on my book cover on the Cover Generator page in Pressbooks, and I can click "Make PDF Cover" or "Make Ebook Cover."

Actual behaviour

I add the information that I want on my book cover on the Cover Generator page in Pressbooks, but when I try to generate a cover, the buttons to do so cannot be clicked.

Steps to reproduce the problem

1. Open a book's dashboard. Go to the Cover Generator page (under the Export tab).
2. Enter basic book information.
3. Try to click "Make PDF Cover"

[bdolor]

The server dependencies required are installed, but may not have the correct/latest version. Not related to the plugin at all, but will leave it here.

[bdolor]

resolved via https://github.com/pressbooks/pressbooks/pull/1467

[josieg]

I can create a PDF cover no problem, but when I try to generate an eBook cover I get the following error message:

[bdolor]

proposed resolution via https://github.com/pressbooks/pressbooks/pull/1474