forward zone help

[Gie]

hi all,
i have problem when figure out forward zone, and this is my configuration
in named.conf with ip addr 10.10.10.1/24:

zone "mydomain.com"{
	type master;
       file "db.mydomain.com";
        allow-query {
                any;
        };
        allow-transfer {
                any;
        };
};
        
zone "jkt.mydomain.com" {
        type forward;
        forwarders {
                10.10.9.1;
                10.10.9.2;
        };
};

the prob is a domain under "jkt.mydomain.com" can't resolve

regards,
-Gian-