DNS filter not working

Elastic Stack Logstash
3

Hay Rcowart

thank for this i just tried and with no luck i changed your filter you gave me to this

filter {

mutate {
    add_field => { "hostname" => "%{host}"}
}
dns {
    reverse => [ "hostname" ]
    action => "replace"

    # CUSTOMIZE THE FOLLOWING VALUES AS REQUIRED BY YOUR ENVIRONMENT!
    nameserver => [ "XX.X.X.X" ]
    hit_cache_size => 4096
    hit_cache_ttl => 900
    failed_cache_size => 512
    failed_cache_ttl => 900
}

}

Can you see an issue with this config?

i also have and extra filter in the config, to just adds an new field what works