Mailgun与PHP

Question

I've been trying to implement a contact service using Mailgun coded in PHP. I receive the following error:

Could not connect to SMTP host

Below is my code:

<?php

require("../includes/config.php");
require("../mailgun-php/vendor/autoload.php");
require("../phpmailer/_lib/class.phpmailer.php");
use Mailgun\Mailgun;

if($_SERVER["REQUEST_METHOD"] === "GET")
{
    render("contact-form.php", ["title" => "Contact us"]);
}

if($_SERVER["REQUEST_METHOD"] === "POST")
{     

    $mail = new PHPMailer;

    $mail->isSMTP();  // Set mailer to use SMTP
    $mail->Host = 'smtp.mailgun.org';  // Specify mailgun SMTP servers
    $mail->SMTPAuth = true; // Enable SMTP authentication
    $mail->Username = 'postmaster@sandboxb9cc446d8b7240efa59917c68fae6e50.mailgun.org'; // SMTP username from https://mailgun.com/cp/domains
    $mail->Password = '*SMTP password from sandbox domain'; // SMTP password from https://mailgun.com/cp/domains
    $mail->SMTPSecure = 'sll';   // Enable encryption, 'ssl'
            $mail->Port= '465';

    $mail->From = 'sandboxb9cc446d8b7240efa59917c68fae6e50.mailgun.org'; // The FROM field, the address sending the email 
    $mail->FromName = 'Enquiry bot'; // The NAME field which will be displayed on arrival by the email client
    $mail->addAddress('****@gmail.com');     // Recipient's email address and optionally a name to identify him
    $mail->isHTML(true);   // Set email to be sent as HTML, if you are planning on sending plain text email just set it to false

    // The following is self explanatory
    $mail->Subject = 'Client enquiry';
    $mail->Body    = $_POST["message"];

    if(!$mail->send())
    {  
        echo "Message hasn't been sent.";
        echo 'Mailer Error: ' . $mail->ErrorInfo . "\n";
    } 
    else 
    {
        redirect("confirmation.html");
    }
}
?>

Note that this is the controller (I'm using MCV).
This is part of a website I've been implementing as a project for a CS class. Therefore I would avoid buying a private domain.

UPDATE : I've modified the original post with how this piece of code should be. May anyone else encounter this issue, this snippet is working without any issue.

Answer 1

I've contacted the Mailgun staff which provided me with excellent support. The problem lies with how I specify the port. It should be 465 for SSL and 587 for TLS.