Issue The limit on serial number changes was reached

[sfsdg]

Hi,
I want to create a subdomain over Plesk API. Sending create domain xml data to my server. Subdomain is created. But returning ERR_EMPTY_RESPONSE. If I look at my logs, I see this strings;

The limit on serial number changes was reached No more DNS zone changes can be carried out today.

System info;

Product version: Plesk Onyx 17.5.3
OS version: Ubuntu 16.04


Subdomain is created but server is not respond to me. Here is my test code.

$xml = '<?xml version="1.0"?>
<packet>
    <subdomain>
        <add>
            <parent>mywebsite.com</parent>
            <name>my-sub-domain</name>
            <property>
                <name>php</name>
                <value>1</value>
            </property>
            <property>
                <name>www_root</name>
                <value>/my-sub-domain.mywebsite.com</value>
            </property>
            <property>
                <name>ftp_login</name>
                <value>admin</value>
            </property>
            <property>
                <name>ftp_password</name>
                <value>admin</value>
            </property>
        </add>
    </subdomain>
</packet>';


        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL,"https://server_addr:8443/enterprise/control/agent.php");
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $xml);
        curl_setopt ($ch, CURLOPT_FOLLOWLOCATION, 0);

        $headers = [
            'Content-Type: text/xml',
            'HTTP_PRETTY_PRINT: TRUE',
            'KEY: e3b6e31d-3483-a22b-8edc-69c4f991fca4'
        ];

        curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
        $server_output = curl_exec ($ch);
        dd($server_output);

        curl_close($ch);