Laravel FCM Notifications Reported as Sent but Not Delivered to Devices

I am using the laravel-notification-channels/fcm package to send notifications to all my devices. I have a DeviceToken model and table that stores all device/Firebase Cloud Messaging (FCM) tokens.

DeviceToken.php Model

PHPCopied
<?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;
use Illuminate\Notifications\Notifiable;

class DeviceToken extends Model
{
    use Notifiable;

    protected $fillable = ['fcm_token'];

    public static function getAllTokens(): array
    {
        return self::pluck('fcm_token')->toArray();
    }
}

I also have a notifications table. Whenever a new notification record is created, my observer sends the notification to all devices rather than to specific users.

Below is my SendNotification.php Notification class:

PHPCopied
<?php

namespace App\Notifications;

use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Notifications\Notification;
use NotificationChannels\Fcm\FcmChannel;
use NotificationChannels\Fcm\FcmMessage;
use NotificationChannels\Fcm\Resources\Notification as FcmNotification;

class SendNotification extends Notification
{
    public $title;
    public $body;

    /**
     * Create a new notification instance.
     */
    public function __construct($title, $body)
    {
        $this->title = $title;
        $this->body = $body;
    }

    public function via($notifiable)
    {
        return [FcmChannel::class];
    }

    /**
     * Get the mail representation of the notification.
     */
    public function toFcm($notifiable): FcmMessage
    {
        return (new FcmMessage(notification: new FcmNotification(
            title: $this->title,
            body: $this->body
        )))
            ->data(['data1' => 'value', 'data2' => 'value2'])  // Additional data
            ->custom([
                'android' => [
                    'notification' => [
                        'color' => '#0A0A0A',
                    ],
                ],
                'apns' => [
                    'fcm_options' => [
                        'analytics_label' => 'analytics',
                    ],
                ],
            ]);
    }
}

And here is my NotificationObserver.php which is triggered after a new notification is created in the database:

PHPCopied
<?php

namespace App\Observers;

use App\Models\DeviceToken;
use App\Models\Notification;
use App\Notifications\SendNotification;
use Illuminate\Contracts\Events\ShouldHandleEventsAfterCommit;
use Illuminate\Support\Facades\Log;
use Illuminate\Support\Facades\Notification as NotificationFacade;
use NotificationChannels\Fcm\FcmChannel;

class NotificationObserver implements ShouldHandleEventsAfterCommit
{
    /**
     * Handle the Notification "created" event.
     */
    public function created(Notification $notification): void
    {
        // Fetch all FCM tokens from the device_tokens table
        $deviceTokens = DeviceToken::getAllTokens();

        if (!empty($deviceTokens)) {
            // Send the notification via FCM
            try {
                // Optionally, chunk the tokens if you have many (e.g., 500)
                $chunkSize = 500;
                $chunks = array_chunk($deviceTokens, $chunkSize);

                foreach ($chunks as $chunk) {
                    NotificationFacade::route(FcmChannel::class, $chunk)
                        ->notify(new SendNotification($notification->title, $notification->body));
                }

                Log::channel("notification")->info("Notification sent to " . count($deviceTokens) . " devices.");
            } catch (\Exception $e) {
                Log::channel("notification")->error("Error sending notification: " . $e->getMessage());
            }
        } else {
            Log::channel("notification")->warning("No device tokens found");
        }
    }
}

My logs indicate that notifications are sent:

LOGCopied
[2025-01-30 15:41:25] local.INFO: Notification sent to 3 devices.  
[2025-01-30 15:42:14] local.INFO: Notification sent to 3 devices.  

However, no devices are actually receiving any notifications. I have verified that no errors are reported in the logs, so I suspect there might be an issue with the FCM configuration, device tokens, or notification message structure. Any insights or troubleshooting steps would be greatly appreciated as I am stuck with this issue.