当授权密钥是我的服务器密钥时的 Firebase MismatchSenderID

I'm pretty lost actually, since that all MismatchSenderId errors were resolved with replacing with the correct server key.

    <?php 
    require "dbconfig.php";

    $sql = "SELECT token FROM tokendb";
    $result = mysql_query($sql) or die($sql."<br/><br/>".mysql_error());
    $tokens = array();

    while($row = mysql_fetch_assoc($result))
    {
        echo $row['token']; //this shows the same token compared to the token show in logcat(visual studio)
        $tokens[] = $row["token"];

      echo '<form id="form1" name="form1" method="post" action="">'.
    '<p>From<br>'.
    '<input type="text" size="100" maxlength="100" name="From" id="From" /><br>'.
    '<p>Title<br>'.
    '<input type="text" size="100" maxlength="100" name="Title" id="Title" />'.
    '<br>'.
    '<input type="submit" name="Send" id="Send" value="Send" />'.
    '</form>';

    }

    $message = array("message" => "notification test");
    $message_status = sendFCMMessage($message, $tokens);
    echo $message_status;

    function sendFCMMessage($message,$target){

       //FCM API end-point
       $url = 'https://fcm.googleapis.com/fcm/send';

       $fields = array();
       $fields['body'] = $message;
       if(is_array($target)){
        $fields['registration_ids'] = $target;
       }else{
        $fields['to'] = $target;
       }

       //header with content_type api key
       $headers = array(
        'Content-Type:application/json',
            'Authorization:key=********'
       );
       //CURL request to route notification to FCM connection server (provided by Google)           
       $ch = curl_init();
       curl_setopt($ch, CURLOPT_URL, $url);
       curl_setopt($ch, CURLOPT_POST, true);
       curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
       curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
       curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
       curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
       curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
       $result = curl_exec($ch);
       if ($result === FALSE) {
        die('Oops! FCM Send Error: ' . curl_error($ch));
       }
       curl_close($ch);
       return $result;
    }

    ?>

EDIT:这个简短的 php 代码也给了我 MismatchSenderId 错误

  <?php
$ch = curl_init("https://fcm.googleapis.com/fcm/send");
$header=array('Content-Type: application/json',
"Authorization: key=***(serverkey from project)");
curl_setopt($ch, CURLOPT_HTTPHEADER, $header);
curl_setopt( $ch,CURLOPT_SSL_VERIFYPEER, false );

curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, "{ "notification": {    "title": "Test desde curl",    "text": "Otra prueba"  },    "to" : "my device's token"}");

curl_exec($ch);
curl_close($ch);
?>