使用PHP通过REST调用Xbox Services API遇授权及请求错误求助

作为学习练习，我尝试通过REST接口访问Xbox Services API，缺乏API使用经验，参照微软《MS users batch profile settings post》指南编写了PHP POST请求代码：

$url = "https://profile.xboxlive.com/users/batch/profile/settings";
$data = array(
    "userIds" => ["2533274791381930"],
    "settings" => ["GameDisplayName", "GameDisplayPicRaw", "Gamerscore", "Gamertag"]
);

$options = array(
    'http' => array(
        'header'  => "x-xbl-contract-version: 2\r\n".
                     "Content-Type: application/json\r\n",                   
        'method'  => 'POST',
        'content' => json_encode($data),
    ),
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);
echo $result;

运行后出现错误：

Warning: file_get_contents(https://profile.xboxlive.com/users/batch/profile/settings): Failed to open stream: HTTP request failed! HTTP/1.1 401 Unauthorized

该错误提示需要授权，但指南未提及令牌相关内容。我在Azure Portal配置应用后，更新代码添加了AccessToken获取逻辑：

$clientId = 'xxxxxxxxxxxxxxxxxxx';
$clientSecret = 'yyyyyyyyyyyyyyyyyyyy';
$grantType = 'client_credentials';
$scope = 'https://graph.microsoft.com/.default';

// Get an access token
$tokenUrl = 'https://login.microsoftonline.com/common/oauth2/v2.0/token';
$data = array(
    'client_id' => $clientId,
    'client_secret' => $clientSecret,
    'grant_type' => $grantType,
    'scope' => $scope
);

$options = array(
    'http' => array(
        'header'  => "Content-type: application/x-www-form-urlencoded\r\n",
        'method'  => 'POST',
        'content' => http_build_query($data),
    ),
);

$context  = stream_context_create($options);
$result = file_get_contents($tokenUrl, false, $context);
$accessToken = json_decode($result)->access_token;

// Make a request to the API
$url = "https://profile.xboxlive.com/users/batch/profile/settings";
$data = array(
    "userIds" => ["2533274791381930"],
    "settings" => ["GameDisplayName", "GameDisplayPicRaw", "Gamerscore", "Gamertag"]
);

$options = array(
    'http' => array(
        'header'  => "Authorization: Bearer ".$accessToken."\r\n".
                      "x-xbl-contract-version: 2\r\n".
                     "Content-Type: application/json\r\n",
        'method'  => 'POST',
        'content' => json_encode($data),
    ),
);

$context  = stream_context_create($options);
$result = file_get_contents($url, false, $context);
echo $result;

运行后出现新错误：

file_get_contents(https://login.microsoftonline.com/common/oauth2/v2.0/token): Failed to open stream: HTTP request failed! HTTP/1.1 400 Bad Request

我不确定当前方向是否正确，感觉代码本身没问题但可能遗漏了步骤，全程只用PHP实现未使用中间件或第三方API。另外想了解是否必须加入Xbox Live创作者计划才能访问该API，网上相关信息存在冲突，恳请技术建议。

内容的提问来源于stack exchange，提问作者Dan Twining