Why don't I receive Cloud Messaging notifications?

Question

PHP

I am writing a server part to send notifications to a specific user on a device. In the response, the message is sent, but in fact it does not arrive. The main thing from the Console - come. What could be the problem?

$tokens = array();
  $tokens[0] = '!!!';
  $message = array("message" => '12345');
  
  $url = 'https://fcm.googleapis.com/fcm/send';
  
  $fields = array(
      'registration_ids' => $tokens,
      'data' => $massage
      );
      
  $headers = array(
      'Authorization:key = !!!',
      'Content-Type: application/json'
      );
      
  $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
    curl_setopt($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));
  echo "---".$ch."---";
  
    $result = curl_exec($ch);           
    if ($result === FALSE) {
        die('Curl failed: ' . curl_error($ch));
    }
    curl_close($ch);

  
  echo $result;

{"multicast_id":6833045560665960461,"success":1,"failure":0,"canonical_ids":0,"results":[{"message_id":"0:1565387661837510%836c9c22f9fd7ecd"}]}

Answer 1

I'm a little lazy to figure it out, but, right off the bat, a question. Why not use the official sdk ? m?

Answer 2

Perhaps it's a typo:
$message / $massage
Not familiar with php, does he swear in such cases, or is silent?
UPD:
Judging by the answer fcm, Google accepts the request. And it must be delivered to the mobile. A similar scheme works fine for me, the only difference is that I send not as a list, but to one device.
There may be a problem on the receiving end. How do you process an incoming message? With these parameters (specified "data", but no "notification"), there will be no automatic pop-up notification - the message must be processed programmatically on the mobile.