使用Kreait的Firebase推送通知

Im using Kreait for sending my firebase push notifications. Ive successfully implemented it but eveytime I try to send the request I get a 404 url does not exist error (Client error: POST https://fcm.googleapis.com/v1/projects/project-id/messages:send resulted in a `404 Not Found). I have my google authentication json file in the same directory as my php files.

Code:

$serviceAccount = ServiceAccount::fromJsonFile(__DIR__.'/google.json');

$firebase = (new Factory)
        ->withServiceAccount($serviceAccount)
        // The following line is optional if the project id in your credentials file
        // is identical to the subdomain of your Firebase project. If you need it,
        // make sure to replace the URL with the URL of your project.
        //->withDatabaseUri('https://my-project.firebaseio.com')
        ->create();

$messaging = $firebase->getMessaging();

$deviceToken = 'token';

$notification = Notification::create("test", "body");
$data = [
   'first_key' => 'First Value',
   'second_key' => 'Second Value',
];

$message = CloudMessage::withTarget('token', $deviceToken)
     ->withNotification($notification) // optional
     ->withData($data);

// error here
// 404 Client error: `POST https://fcm.googleapis.com/v1/projects/projectid/messages:send` resulted in a `404 Not Found
$messaging->send($message);

use ->withDatabaseUri('https://INSERT_YOUR_PROJECT_ID_HERE.firebaseio.com') ... while it appears, that most likely that __DIR__.'/google.json' (which is usually called google-services.json) does not exist, therefore the project URL will be unknown. in every case, that projectid in the URL has to be replaced with the actual project_id... maybe check the existence of that file with if(! file_exists(__DIR__.'/google.json')) {die('config absent.');}?