MailChimp API Responds 404 in V3.0 PHP Curl - php

Question

I am using the following code to initiate a member add request to a list in MailChimp.
<?php
error_reporting(-1);
ini_set('display_errors', 1);
$email = 'test#domain.com';
$first_name = 'name';
$last_name = 'last name';
$api_key = 'xx-us18'; // YOUR API KEY
// server name followed by a dot.
// We use us13 because us13 is present in API KEY
$server = 'us18.';
$list_id = 'xx'; // YOUR LIST ID
$auth = base64_encode( 'user:'.$api_key );
$data = array(
'apikey' => $api_key,
'email_address' => $email,
'status' => 'subscribed',
'merge_fields' => array(
'FNAME' => $first_name,
'LNAME' => $last_name
)
);
$json_data = json_encode($data);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://'.$server.'api.mailchimp.com/3.0/lists/'.$list_id.'/members');
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json',
'Authorization: Basic '.$auth));
curl_setopt($ch, CURLOPT_USERAGENT, 'PHP-MCAPI/2.0');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, $json_data);
$result = curl_exec($ch);
echo $result;
?>
But what happened is the response is 404.
{
type: "http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/",
title: "Resource Not Found",
status: 404,
detail: "The requested resource could not be found.",
instance: "78a35efa-ef43-471d-9e70-aecdc992d2e6"
}
Does anyone know what I am doing wrong? What might be the reason for this error?
Extra Infos: API Key is valid, If I provide that wrong, I am getting another error.
List-id is also true.
I am running this code on localhost with MAMP.

Answer 1

The issue was I used web_id instead of list_id.
When I changed that, the issue was resolved.