Laravel mail - how to debug Mailgun - laravel

Question

I'm trying to set up mailgun with laravel (5.3) but returns null, doesn't shows error and doesn't send email. Also i tried this mailgun params with PHP CURL, its working as well. Also i have set MAIL_DRIVER=log its working to. How i can debug Laravel Mailgun?
I have installed Guzzle.
I dont install Laravel Queue system. Can be problem because of this?
My log:
[2019-08-06 13:19:04] local.DEBUG: Message-ID:
<21f27....9cf293be62#todo.test>
Date: Tue, 06 Aug 2019 13:19:04 +0000
Subject: Activate Your Account
From: s....#gmail.com
To: s....#gmail.com
MIME-Version: 1.0
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable
<h2>this is test mail</h2>
<p>Lorem ipsum dolor sit amet, consectetur</p>
My .env params
MAIL_DRIVER=mailgun
MAIL_HOST=smtp.mailgun.org
MAIL_PORT=2525 //tried other ports 25, 587, and 465
MAIL_USERNAME=postmaster#sandbox5....a6df0f425dfd0.mailgun.org
MAIL_PASSWORD=f6ae0....b4e0a8205b-73ae490d-d2e10d3d
MAIL_ENCRYPTION=TLS
MAILGUN_DOMAIN=sandbox.....f0f425dfd0.mailgun.org
MAILGUN_SECRET=56cc50b....10c62e08-73ae490d-11f1b30a
MAIL_FROM_ADDRESS=postmaster#sandb....df0f425dfd0.mailgun.org
MAIL_FROM_NAME=ToDo
My Contrller
Mail::to('m....r#gmail.com')->send(new SendMail());
if(count(Mail::failures()) > 0){
return 'Failed to send password reset email, please try again.';
}
My Mail class
public function build()
{
return $this->from('postmaster#san....0f425dfd0.mailgun.org')
->subject('Activate Your Account')
->view('emails.test');
}

Answer 1

I find problem, in config/services.php
'mailgun' => [
'domain' => 'https://api.mailgun.net/v3/sandbox53bb3c32cee7449f961a6df0f425dfd0.mailgun.org',
'secret' => '56cc50bafb9320f2ef3c9d3210c62e08-73ae490d-11f1b30a',
],
Changed to
'mailgun' => [
'domain' => 'sandbox53bb3c32cee7449f961a6df0f425dfd0.mailgun.org',
'secret' => '56cc50bafb9320f2ef3c9d3210c62e08-73ae490d-11f1b30a',
],
Then returns
Client error: `POST https://api.mailgun.net/v3/dfd0.mailgun.org/messages.mime` resulted in a `400 BAD REQUEST` response:
{
"message": "Sandbox subdomains are for test purposes only. Please add your own domain or add the address to authoriz (truncated...)
Eventually mailgun API works