Grails 3.0.2 secured application respond 406 Not Acceptable - http

Question

I'm working with a very simple application using Grails 3.0.2, secured with Spring Security Core Plugin version 3.0.0.M1. I have only one Book domain with fields title, author and content and run the generate-all script for that domain. The problem is that when I try go to /book/index, after successfully logged in, I get an http "406 Not Acceptable" error.
This is my http request header:
GET /book/index HTTP/1.1
Host: localhost:8080
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:39.0) Gecko/20100101 Firefox/39.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8
Accept-Language: it-IT,it;q=0.8,en-US;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
Referer: http://localhost:8080/login/auth
Cookie: _ga=GA1.1.1278470533.1431342674; JSESSIONID=7DE58D010998C57939E6258A7148F0C6
Connection: keep-alive
Cache-Control: max-age=0
and response:
HTTP/1.1 406 Not Acceptable
Server: Apache-Coyote/1.1
X-Application-Context: application:development
Content-Type: text/html;charset=ISO-8859-1
Content-Language: it-IT
Content-Length: 312
Date: Fri, 04 Sep 2015 07:39:37 GMT
I've resolved problem adding:
static responseFormats = ['html', 'xml', 'json']
in my controller.
Can you help me with an explanation of what happened and/or give better solutions?
Thanks in advance for your help.