Mailchimp API在1-2个php表单提交后停止工作

Question

I'm using a simple code to add new leads to my mailchimp account. It worked perfect a few times and then I tried again 10 minutes later and it stopped working.

Is there some sort of API limit or something?

// MailChimp API URL
$memberID = md5(strtolower($email));
$dataCenter = substr($apiKey,strpos($apiKey,'-')+1);
$url = 'https://' . $dataCenter . '.api.mailchimp.com/3.0/lists/' . $listID . '/members/' . $memberID;

// member information
$json = json_encode([
    'email_address' => $email,
    'status'        => 'subscribed',
    'merge_fields'  => [
        'FNAME'     => $fname,
        'LNAME'     => $lname
    ]
]);

// send a HTTP POST request with curl
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_USERPWD, 'user:' . $apiKey);
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_TIMEOUT, 10);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, $json);
$result = curl_exec($ch);
$httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);