Hello there,
The URL of the pressbook instance i’m working on has a ‘-‘ in it (e-publish.uliege.be) so when users try to duplicate a book, they have an alert showing « The URL of your book can only contain lowercase characters (a-z) and numbers » and can’t proceed.
So for now i’m using a plugin to export books but it would be easier to use the in-house tools.
Would it be possible for you to accept the ‘-‘ in URL or should I change it ?
Thank you ! 
Greetings Charlotte,
This hyphen is for the book name only, not the domain name. So https://e-publish.uliege.be/book-name/ would not be allowed, but https://e-publish.uliege.be/bookname/ would. When you try to create a new book in Pressbooks, it will disallow a URL with a hyphen in it. Perhaps this is what you’re seeing?
To add to Christopher’s response, network managers and super admins can edit book URLs and add special characters (like dashes), which are disallowed when creating or cloning new books. We generally don’t recommend it, because it can lead to situations like this, but some people do it anyways. It’s possible that this is what’s happened here.
If that’s the case, you can simply clone to a new URL that doesn’t contain the dashes. For example, see the screenshot below (which will work with our cloning routine):
If you really needed to and had sufficient permissions on the network, you could then edit the URL post-clone and add the hyphens back in.
