laravel keep sending notifications from firebase code example

Example: laravel firebase cloud messaging notifications

// Install this package
composer require laravel-notification-channels/fcm:~2.0

// Create a notification for user and add the following code
class AccountActivated extends Notification
{
    public function via($notifiable)
    {
        return [FcmChannel::class];
    }

    public function toFcm($notifiable)
    {
        return FcmMessage::create()
            ->setData(['data1' => 'value', 'data2' => 'value2'])
            ->setNotification(\NotificationChannels\Fcm\Resources\Notification::create()
                ->setTitle('Account Activated')
                ->setBody('Your account has been activated.')
                ->setImage('http://example.com/url-to-image-here.png'))
            ->setAndroid(
                AndroidConfig::create()
                    ->setFcmOptions(AndroidFcmOptions::create()->setAnalyticsLabel('analytics'))
                    ->setNotification(AndroidNotification::create()->setColor('#0A0A0A'))
            )->setApns(
                ApnsConfig::create()
                    ->setFcmOptions(ApnsFcmOptions::create()->setAnalyticsLabel('analytics_ios')));
    }
}

// Add Notifiable trait to user class
// Add Method routeNotificationForFcm to return save token from firebase cloud messaging in database 

class User extends Authenticatable
{
    use Notifiable;

    /**
     * Specifies the user's FCM token
     *
     * @return string
     */
    public function routeNotificationForFcm()
    {
        return $this->fcm_token;
    }
}


// Fire the notification to test it
$user->notify(new AccountActivated);