PHP Mailer - 454 TLS connection failed

Question

On my page I have a contact form which uses PHP Mailer. At the beginning, for testing purposes only, I used it with my Gmail account. Everything worked like a charm. Then I decided to change the e-mail service from Gmail to one which comes from my hosting provider. Then the problems have started. Every time I attempt to send an email, an exception occurs:

2020-05-13 20:53:44 CLIENT -> SERVER: STARTTLS
2020-05-13 20:53:44 SERVER -> CLIENT: 220 ready for tls
SMTP Error: Could not connect to SMTP host.
2020-05-13 20:53:44 CLIENT -> SERVER: QUIT
2020-05-13 20:53:44 SERVER -> CLIENT: 454 TLS connection failed: error:14094410:SSL routines:SSL3_READ_BYTES:sslv3 alert handshake failure (#4.3.0)
2020-05-13 20:53:44 SMTP ERROR: QUIT command failed: 454 TLS connection failed: error:14094410:SSL routines:SSL3_READ_BYTES:sslv3 alert handshake failure (#4.3.0)

This is my code for sending an e-mail:

<?php

    use PHPMailer\PHPMailer\PHPMailer;
    use PHPMailer\PHPMailer\Exception;
    use PHPMailer\PHPMailer\SMTP;

    require 'PHPMailer.php';
    require 'SMTP.php';
    require 'Exception.php';

    class Mailer
    {
        private $mail;

        public function __construct($host, $user, $password, $port = 587)
        {
            $this->mail = new PHPMailer();
            try
            {
                $this->mail->SMTPDebug = SMTP::DEBUG_SERVER;  
                $this->mail->CharSet    = "UTF-8";
                $this->mail->isSMTP();
                $this->mail->Host       = $host;
                $this->mail->SMTPAuth   = true;
                $this->mail->SMTPSecure = 'ssl';
                $this->mail->Username   = $user;
                $this->mail->Password   = $password;
                $this->mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
                $this->mail->Port       = $port;
            }
            catch(Exception $e)
            {
                echo "Exception: " . $e;
            }
        }

        public function Send($from, $alias, $to, $subject, $body, $cc)
        {
            try
            {
                $this->mail->setFrom($from, $alias);
                $this->mail->addAddress($to);

                $this->mail->isHTML(true);
                $this->mail->Subject = $subject;
                $this->mail->Body    = $body;

                if($cc !== '')
                {
                    $this->mail->AddCC($cc);
                }

                if(!$this->mail->send())
                {
                    die($this->mail->ErrorInfo);
                }

                return true;
            }
            catch (Exception $e)
            {
                return false;
            }
        }

I suppose I configure PHP Mailer wrongly when it comes to TLS/SSL, as I am pretty newbie to this. It may be an expedient information that my webpage uses TLS 1.3 encryption

Answer 1

Here's a tip, if it works, don't forget a vote to strengthen. Let's go to the settings ...

$mail->SMTPOptions = array(
    'ssl' => array(
        'verify_peer' => false,
        'verify_peer_name' => false,
        'allow_self_signed' => false
    )
);

Remember that this is a palliative solution to work immediately, but I recommend investigating the problem. Another detail do tests using ports 465 and 587 sometimes it can be that!

$mail->Port = "587";
$mail->SMTPSecure = "tls";

Another thing I didn't understand ... why would I be using $ this->mail->SMTPSecure twice?

 $this->mail->SMTPSecure = 'ssl';
 $this->mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;