突然碰到這個錯誤，'RuntimeException’ with message ‘CURL connection

PHP Fatal error:  Uncaught exception 'RuntimeException' with message 'CURL connection (https://idx4lztp.api.lncld.net/1.1/classes/Transactions?limit=0&count=1) error: 28 Operation timed out after 15001 milliseconds with 0 out of 0 bytes received' in /public_html/vendor/leancloud/leancloud-sdk/src/LeanCloud/Client.php:433
Stack trace:
#0 /public_html/vendor/leancloud/leancloud-sdk/src/LeanCloud/Client.php(463): LeanCloud\Client::request('GET', '/classes/Transa...', Array, NULL, Array, NULL)
#1 /public_html/vendor/leancloud/leancloud-sdk/src/LeanCloud/Query.php(760): LeanCloud\Client::get('/classes/Transa...', Array)
#2 /public_html/executeFiles/logistics/test.php(12): LeanCloud\Query->count()
#3 {main}
  thrown in /public_html/vendor/leancloud/leancloud-sdk/src/LeanCloud/Client.php on line 433

我已经以最简单的query去找问题，但还是看不懂原因。

<?php

require '../../vendor/autoload.php';
require_once("../leancloudKey.php");
use \LeanCloud\Client;
use \LeanCloud\CloudException;
use \LeanCloud\Query;
Client::initialize($leancloudAppId, $leancloudAppKey, $leancloudMasterKey);
Client::setServerUrl($leancloudServerUrl);

$query = new Query("Transactions");
echo "count: " . $query->count() . "\n";

?>

请问应该怎么去排查？