"Caching disabled by Authcache Config" message using File Cache

I have installed the module and File Cache module too. On my settings.php the config is:

/**
 * Use File Cache for the page cache and authcache keys.
 */

$conf['cache_backends'][] = 'sites/all/modules/filecache/filecache.inc';
$conf['cache_backends'][] = 'sites/all/modules/authcache/authcache.cache.inc';
$conf['cache_backends'][] = 'sites/all/modules/authcache/modules/authcache_builtin/authcache_builtin.cache.inc';
$conf['cache_default_class'] = 'DrupalFileCache';
$conf['cache_class_cache_page'] = 'DrupalFileCache';


/**
 * When serving cached pages, do not bother connecting to the database.
 */
$conf['authcache_builtin_cache_without_database'] = TRUE;
/**
 * All customized settings influencing page delivery need to be set here.
 */
// Deliver gzip compressed pages if possible
$conf['page_compression'] = 1;
// Allow browsers to store the page for up to 10 minutes
$conf['page_cache_maximum_age'] = 600;

On the status report it says:

Authcache	hook_authcache_backend_cache_save() implemented: authcache_builtin OK
Authcache builtin cache backend	Using DrupalFileCache as cache backend

And on the configuration I have set the proper roles. Having the debug module active I got this message when I browse the pages with the proper role:

"Caching disabled by Authcache Config"

If I click on it it takes me to the debug configuration, but checking that page and the configuration page, I don't find anything wrong. What is happening?