whmcsZimbraSingle/api/zmtest.php

<?php
ini_set('soap.wsdl_cache_enabled',0);
ini_set('soap.wsdl_cache_ttl',0);


require_once("config.php");

require_once("Zm/Auth.php");
require_once("Zm/Account.php");
require_once("Zm/Domain.php");
require_once("Zm/Server.php");

$auth = new Zm_Auth($zimbraServer, $zimbraAdminEmail, $zimbraAdminPassword, "admin");

$l = $auth->login();

if(is_a($l, "Exception")) {

    echo "Error : cannot login to $zimbraServer\n";

    echo $l->getMessage()."\n";

    exit();

}

$accountManager = new Zm_Account($auth);
$r = $accountManager->accountExists("test3@thurdata.local");
echo "$r\n";
$r = $accountManager->accountExists("test5@thurdata.local");
echo "$r\n";