GCE上でcakephp3のHttpClientを利用するとエラーになります

前提・実現したいこと

cakephp3でWebアプリケーションを作り、GCE上で動かしています。
HttpClientを利用して、外部のAPIを叩こうとした時に以下のエラーが発生しました。

発生している問題・エラーメッセージ

2018-06-20 17:14:19 Error: [Cake\Core\Exception\Exception] fopen(): php_network_getaddresses: getaddrinfo failed: Name or service not known
fopen(https:/XXXX): failed to open stream: php_network_getaddresses: getaddrinfo failed: Name or service not known
Request URL: /XXX/?callback=jQuery33100918089472164082_1529482454011
Referer URL: https://{request_host}/XXX/
Stack Trace:
#0 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Client/Adapter/Stream.php(252): Cake\Http\Client\Adapter\Stream->_open(Object(Zend\Diactoros\Uri))
#1 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Client/Adapter/Stream.php(82): Cake\Http\Client\Adapter\Stream->_send(Object(Cake\Http\Client\Request))
#2 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Client.php(430): Cake\Http\Client\Adapter\Stream->send(Object(Cake\Http\Client\Request), Array)
#3 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Client.php(399): Cake\Http\Client->_sendRequest(Object(Cake\Http\Client\Request), Array)
#4 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Client.php(366): Cake\Http\Client->send(Object(Cake\Http\Client\Request), Array)
#5 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Client.php(229): Cake\Http\Client->_doRequest('GET', 'https://{request_host}', NULL, Array)
#6 /usr/local/apache/vhosts/{my_host}/htdocs/src/Controller/Api/XXXController.php(489): Cake\Http\Client->get('https:/request_host}')
#7 /usr/local/apache/vhosts/{my_host}/htdocs/src/Controller/Api/XXXController.php(406): App\Controller\Api\XXXController->__hogeAction('XXX')
#8 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Controller/Controller.php(596): App\Controller\Api\XXXController->invite()
#9 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/ActionDispatcher.php(120): Cake\Controller\Controller->invokeAction()
#10 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/ActionDispatcher.php(94): Cake\Http\ActionDispatcher->_invoke(Object(App\Controller\Api\XXXController))
#11 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/BaseApplication.php(228): Cake\Http\ActionDispatcher->dispatch(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response))
#12 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Runner.php(65): Cake\Http\BaseApplication->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response), Object(Cake\Http\Runner))
#13 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Routing/Middleware/RoutingMiddleware.php(158): Cake\Http\Runner->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response))
#14 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Runner.php(65): Cake\Routing\Middleware\RoutingMiddleware->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response), Object(Cake\Http\Runner))
#15 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Routing/Middleware/AssetMiddleware.php(88): Cake\Http\Runner->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response))
#16 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Runner.php(65): Cake\Routing\Middleware\AssetMiddleware->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response), Object(Cake\Http\Runner))
#17 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Error/Middleware/ErrorHandlerMiddleware.php(98): Cake\Http\Runner->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response))
#18 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Runner.php(65): Cake\Error\Middleware\ErrorHandlerMiddleware->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response), Object(Cake\Http\Runner))
#19 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Runner.php(51): Cake\Http\Runner->__invoke(Object(Cake\Http\ServerRequest), Object(Cake\Http\Response))
#20 /usr/local/apache/vhosts/{my_host}/htdocs/vendor/cakephp/cakephp/src/Http/Server.php(98): Cake\Http\Runner->run(Object(Cake\Http\MiddlewareQueue), Object(Cake\Http\ServerRequest), Object(Cake\Http\Response))
#21 /usr/local/apache/vhosts/{my_host}/htdocs/webroot/index.php(34): Cake\Http\Server->run()
#22 {main}

該当のソースコード

(cakePHPの公式にあるサンプルプログラムが動きません)

php
1use Cake\Http\Client;
2$http = new Client();
3$response = $http->get('http://example.com/test.html');
4

試したこと

localhostでは動いています。
もともとSendGridのAPIをphp公式ライブラリを使おうと思いlocalhostでテストして問題なかったので、GCEにアップしました。アップ後SendGridが正しく利用できないので掘り下げて行ったところ、HttpClientの時点でうまく行ってなさそうでした。
ローカルでは動いているので、ソースは問題ないと考えています。
サーバあるいはネットワークの部分だと考えています。
GCE内でcurlを使ってAPIを叩くとうまくいきます。