PHP中的FCM推送通知显示错误注册无效

Question

我正在使用FCM向我的移动应用发送通知。 但是在运行响应时显示如下错误。

{"multicast_id":6874642050582254124,"success":0,"failure":1,"canonical_ids":0,"results":[{"error":"InvalidRegistration"}]}

我用来在下面给出的php中发送通知的代码。

<?php
$url = 'https://fcm.googleapis.com/fcm/send';
$id='9026c3b17adc17db';
    $fields = array (
            'registration_ids' => array (
                    $id
            ),
            'data' => array (
                    "message" => 'hi'
            )
    );
    $fields = json_encode ( $fields );

    $headers = array (
            'Authorization: key=' . "AdssfdIzaSyBTVEinxXDbH8fyxqJHZNd-NO6O30vIw_dfdfg0",
            'Content-Type: application/json'
    );

    $ch = curl_init ();
    curl_setopt ( $ch, CURLOPT_URL, $url );
    curl_setopt ( $ch, CURLOPT_POST, true );
    curl_setopt ( $ch, CURLOPT_HTTPHEADER, $headers );
    curl_setopt ( $ch, CURLOPT_RETURNTRANSFER, true );
    curl_setopt ( $ch, CURLOPT_POSTFIELDS, $fields );

    $result = curl_exec ( $ch );
    echo $result;
    curl_close ( $ch );


?>