Problem with accentuation when generating epub with gitbook

I'm having trouble generating epub using gitbook . I installed the gitbook-cli and nodejs, then set the book.json file as follows:

{
    "title": "Distribuição Debian",
    "description": "...",
    "author": "Fábio",
    "language": "pt"
}

Only by generating epub metadata like title , description and author are "truncated" unrecognizable characters instead of accents ...

Print the quoted characters: