Sending scheduled emails with lumen 8 and mailgun

Question

I have a Lumen app (v8) configured for sending emails using Mailgun. Everything works flawlessly when I send the mail immediately, but when I try to use the "later" method it seems to be ignored. This is what I am using: file app.php

$app->configure('services');
$app->configure('mail');
$app->configure('queue');

$app->alias('mail.manager', Illuminate\Mail\MailManager::class);
$app->alias('mail.manager', Illuminate\Contracts\Mail\Factory::class);

$app->alias('mailer', Illuminate\Mail\Mailer::class);
$app->alias('mailer', Illuminate\Contracts\Mail\Mailer::class);
$app->alias('mailer', Illuminate\Contracts\Mail\MailQueue::class);

$app->make('queue');

the Onboard3.php mail class:

<?php
namespace App\Mail;

use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;
use Illuminate\Support\Facades\DB;

class Onboard3 extends Mailable
{
    use Queueable, SerializesModels;

    /**
     * Create a new message instance.
     *
     * @return void
     */
    public $info;

    public function __construct($info)
    {
        $this->info = $info;
    }

    /**
     * Build the message.
     *
     * @return $this
     */
    public function build()
    {
        return
            $this->from('[email protected]', 'Sender name')
            ->subject("Subject")
            ->view('emails.users.onboard3')
            ->text('emails.users.onboard3_plain');
    }
}

My controller method:

Mail::to([
    '[email protected]'
])
->later(
    Carbon::now()->addMinutes(10000)
    , new Onboard3($recipient)
);