Lighttpd

Hi.

When I starting lighttpd show in error.log:

(server.c.1295) WARNING: unknown config-key: auth.debug (ignored)

I have mod_auth enabled

# lighttpd-enable-mod
Disabled modules: debian-doc dir-listing evhost expire extforward flv-streaming no-www proxy rewrite rrdtool simple-vhost ssi status userdir usertrack
Enabled modules: accesslog auth cgi evasive fastcgi fastcgi-php ssl

My system:

Debian GNU/Linux 9.3 (stretch)
Linux 4.9.0-5-686
lighttpd 1.4.45-1

Module Auth configuration:

# /usr/share/doc/lighttpd/authentication.txt.gz

server.modules                += ( "mod_auth" )

auth.backend                    = "htdigest" 
auth.backend.htdigest.userfile  = "/usr/local/etc/lighttpd-users" 
auth.debug                      = 2

auth.require                    = ("/" =>
                                    (
                                    "method" => "basic",
                                    "realm" => "Access",
                                    "require" => "valid-user" 
                                    ),
                                )

$HTTP["url"] =~ "^/client" {
    auth.require                = ("" =>
                                    (
                                    "method" => "basic",
                                    "realm" => "Access Client",
                                    "require" => "user=user1|user=user2" 
                                    ),
                                )
}

I searched to Google and I did't find nothing that resolve it.

Any thoughts?