2017-12-04 13:34:14 SERVER -> CLIENT: 220 smtp.gmail.com ESMTP y19sm20173980pgv.19 - gsmtp
2017-12-04 13:34:14 CLIENT -> SERVER: EHLO solutions.proprompt.com
2017-12-04 13:34:14 SERVER -> CLIENT: 250-smtp.gmail.com at your service, [103.58.144.11]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING250 SMTPUTF8
2017-12-04 13:34:14 CLIENT -> SERVER: STARTTLS
2017-12-04 13:34:14 SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
SMTP Error: Could not connect to SMTP host.
2017-12-04 13:34:14 CLIENT -> SERVER: QUIT
2017-12-04 13:34:15
2017-12-04 13:34:15
SMTP Error: Could not connect to SMTP host.
Message could not be sent.Mailer Error: SMTP Error: Could not connect to SMTP host.

$mail->SMTPDebug = 2;                                 // Enable verbose debug output
    $mail->isSMTP();                                      // Set mailer to use SMTP
    $mail->Host = 'smtp.gmail.com';  // Specify main and backup SMTP servers
    $mail->SMTPAuth = true;                               // Enable SMTP authentication
    $mail->Username = 'some@email.com';                 // SMTP username
    $mail->Password = 'somepassword';                           // SMTP password
    $mail->SMTPSecure = 'tls';                            // Enable TLS encryption, `ssl` also accepted
    $mail->Port = 587;