PHPMailer EOF error; connection failed. Could not authenticate - php

Question

I'm getting an EOF error. I'm using the basic template with a few subtractions (attachments, cc, etc) and one addition (AuthType='PLAIN').
<?php
require __DIR__ . '/vendor/autoload.php';
$mail = new PHPMailer;
$mail->SMTPDebug = 4; // Enable verbose debug output
$mail->isSMTP(); // Set mailer to use SMTP
$mail->Host = 'smtp.zoho.com'; // Specify main and backup SMTP servers
$mail->SMTPAuth = true; // Enable SMTP authentication
$mail->AuthType = 'PLAIN';
$mail->Username = '*******'; // SMTP username
$mail->Password = '*******'; // SMTP password
$mail->SMTPSecure = 'tls'; // Enable TLS encryption, `ssl` also accepted
$mail->Port = 587; // TCP port to connect to
$mail->setFrom('*************', '*****');
$mail->addAddress('*********', '******'); // Add a recipient
$mail->isHTML(true); // Set email format to HTML
$mail->Subject = 'From phpmailer-test.php';
$mail->Body = 'This is the HTML message body <b>in bold!</b>';
$mail->AltBody = 'This is the body in plain text for non-HTML mail clients';
if(!$mail->send()) {
echo 'Message could not be sent.';
echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
echo 'Message has been sent';
}
?>
-I've tried STMP via 465 both with this script and with telnet and gotten the same error.
-I've tested this with tls and 587 with this script (but not telent) and gotten this error.
-I'm using composer, per the Troubleshooting page's instructions.
-Script is at phillyguitarlessons.com, mail account is at *#kalegood.com (hosted by zoho.com). I don't think this would cause an error, but am not sure.
-I've tried looking through the docs (via a page search for "EOF") and found nothing.
-From my VPS, my ports should be wide-open. To zoho.com
-Opensssl is activated (confirmed via info.php)
Output (switched to debug level 2):
2016-10-03 13:47:40 SERVER -> CLIENT: 220 mx.zohomail.com SMTP Server ready October 3, 2016 6:47:40 AM PDT
2016-10-03 13:47:40 CLIENT -> SERVER: EHLO phillyguitarlessons.com
2016-10-03 13:47:40 SERVER -> CLIENT: 250-mx.zohomail.com Hello phillyguitarlessons.com (162.243.32.109 (162.243.32.109)) 250-STARTTLS 250 SIZE 53477376
2016-10-03 13:47:40 CLIENT -> SERVER: STARTTLS
2016-10-03 13:47:40 SERVER -> CLIENT: 220 Ready to start TLS.
2016-10-03 13:47:41 CLIENT -> SERVER: EHLO phillyguitarlessons.com
2016-10-03 13:47:41 SERVER -> CLIENT: 250-mx.zohomail.com Hello phillyguitarlessons.com (162.243.32.109 (162.243.32.109)) 250-AUTH LOGIN PLAIN 250 SIZE 53477376
2016-10-03 13:47:41 CLIENT -> SERVER: AUTH PLAIN
2016-10-03 13:49:46 SERVER -> CLIENT: 334
2016-10-03 13:49:46 SMTP NOTICE: EOF caught while checking if connected
2016-10-03 13:49:46 SMTP Error: Could not authenticate.
2016-10-03 13:49:46 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting Message could not be sent.Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting