First, let me explain what I'm trying to do:
I have a book which is composed of several chapters. There's a new user who needs access to only a specific chapter in this book, he should be able to create and edit pages in this chapter, but he shouldn't be able to see the other chapters.
Before this modification, I activated custom permission for this book, where group "Telecom" has full access to it, and all chapters inherit this permission. So what I tried to do is: I activated the custom permissions on this chapter, enabled full access to "Telecom" group (to keep this permission), but I also enabled full access to the group this user belongs (it's a "personal" group, only he is in the group). So the permissions are like this:

So, what I realized is that he can't see the book. Ok, that's fine, I think that was expected, he can still access the chapter by using the URL or in the recents panel. The problem is, he can't create new pages, it gives him a 404 error.
I can't understand why this is happening, I gave full access to the chapter, but he still can't create new pages. I can solve this by enabling some permissions on the book itself, but then he would be able to see all the chapters.
First, let me explain what I'm trying to do:
I have a book which is composed of several chapters. There's a new user who needs access to only a specific chapter in this book, he should be able to create and edit pages in this chapter, but he shouldn't be able to see the other chapters.
Before this modification, I activated custom permission for this book, where group "Telecom" has full access to it, and all chapters inherit this permission. So what I tried to do is: I activated the custom permissions on this chapter, enabled full access to "Telecom" group (to keep this permission), but I also enabled full access to the group this user belongs (it's a "personal" group, only he is in the group). So the permissions are like this:
So, what I realized is that he can't see the book. Ok, that's fine, I think that was expected, he can still access the chapter by using the URL or in the recents panel. The problem is, he can't create new pages, it gives him a 404 error.
I can't understand why this is happening, I gave full access to the chapter, but he still can't create new pages. I can solve this by enabling some permissions on the book itself, but then he would be able to see all the chapters.