Facebook getAccessToken错误“不支持的操作数类型”

When I run this code on production I get "Unsupported operand types in " error. FB_APP_ID and FB_SECRET is correct. I think its about my nginx setup. Could you help me?

$fb = new Facebook\Facebook([
    'app_id' => $_ENV['FB_APP_ID'],
    'app_secret' => $_ENV['FB_SECRET'],
    'default_graph_version' => 'v2.3',
]);

$helper = $fb->getJavaScriptHelper();

try {
    $accessToken = $helper->getAccessToken();
    $response = $fb->get('/me?fields=id,name', $accessToken);

} catch (Facebook\Exceptions\FacebookResponseException $e) {

    echo json_encode(['facebook_user_synced' => false]);
    die;
} catch (Facebook\Exceptions\FacebookSDKException $e) {

    echo json_encode(['facebook_user_synced' => false]);
    die;
}

[error] 1305#0: *42 FastCGI sent in stderr: "PHP message: PHP Fatal error: Unsupported operand types in /usr/share/nginx/html/releases/20160726121650/vendor/guzzlehttp/guzzle/src/Client.php on line 234" while reading response header from upstream, client: 162.158.211.205, server: example.com, request: "POST /fbconnect HTTP/1.1", upstream: "fastcgi://127.0.0.1:9000", host: "example.com", referrer: "http://example.com/test_login/JSm15qa2YN"