Windows 通知服务:尝试在 PHP 中创建 Toast 通知时 401 令牌无效

我一直在尝试向模拟器发送 Toast 通知。我创建了 Windows Phone 8.1 应用，并将其与应用商店中的应用相关联。之后，我设法获得了必须用于调用通道 URI 的访问令牌。

当我尝试使用通道 URI 和访问令牌发送 Toast 通知时，出现此错误。

Bearer error="invalid_request",error_description="Invalid token"

这是我创建的 php 测试代码。

<?php
    //GET ACCESS TOKEN
    $tokenRequest = curl_init();
    curl_setopt($tokenRequest, CURLOPT_URL, 'https://login.live.com/accesstoken.srf');
    curl_setopt($tokenRequest, CURLOPT_HTTPHEADER, array(
        'Content-Type: application/x-www-form-urlencoded'
    ));
    //FIELDS
    $fields = array(
        'grant_type' => 'client_credentials',
        'client_id' => '0',
        'client_secret' => 'Q',
        'scope' => 'notify.windows.com'
    );
    $fields_string = "";
    foreach($fields as $key=>$value) { $fields_string .= $key.'='.$value.'&'; }
    rtrim($fields_string, '&');
    curl_setopt($tokenRequest, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($tokenRequest,CURLOPT_POST, count($fields));
    curl_setopt($tokenRequest,CURLOPT_POSTFIELDS, $fields_string);
    $output = json_decode(curl_exec($tokenRequest));
    curl_close($tokenRequest);
    echo "<br>";
    var_dump($output);
    echo "<br>";
    $accessToken = $output->{'access_token'};

    //SEND PUSH
    $sendPush = curl_init();
    curl_setopt($sendPush, CURLOPT_URL, 'https://db3.notify.windows.com/?token=AwYAAABuWLaYT1f9BVJwNJCjc243U1OFXUT8MCqvsME%2ftDnhPG%2f%2fJSurxP3u1y47eqmrQZSPUlZH7koHW3Zwdj5938LYZNRdDyE6JzvyHOZvZvSo%3d');
    //TOAST MESSAGE
    $toastMessage = "<wp:Notification xmlns:wp='"WPNotification'">" .
            "<wp:Toast>" .
            "<wp:Text1>" . "SendToast" . "</wp:Text1>" .
            "<wp:Text2>" . "Text Message" . "</wp:Text2>" .
            "</wp:Toast> " .
            "</wp:Notification>"; 
    curl_setopt($sendPush, CURLOPT_HEADER, true);
    $headers = array('Content-Type: text/xml', "Content-Length: " . strlen($toastMessage), "X-WNS-Type: wns/toast", "Authorization: Bearer $accessToken");
    curl_setopt($sendPush, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($sendPush, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($sendPush,CURLOPT_POST, 1);        
    curl_setopt($sendPush, CURLOPT_POSTFIELDS, $toastMessage);         
    $output = curl_exec($sendPush);
    echo "<br>";
    var_dump(curl_getinfo($sendPush, CURLINFO_HTTP_CODE));
    echo "<br>";
    var_dump(curl_getinfo($sendPush, CURLINFO_HEADER_OUT));
    echo "<br>";
    var_dump($output);
    curl_close($sendPush);
    // Create request to send
?>  

在 c# 中，我使用它来获取通道 URI。

 channel = await PushNotificationChannelManager.CreatePushNotificationChannelForApplicationAsync();
                Debug.WriteLine(channel.Uri);

知道什么可能导致此问题吗？