PHPMailer dev-xoauth failed authentication - oauth-2.0

Question

So I've gone through all of the docs on github - phpmailer xoauth tree to set up my scripts accordingly to use Google's oauth2. I am trying to send an email from the form at halcyonco.io to myself. The domain name is just to live test this site. I encounter the same error when sending the form locally.
My question is when I submit the form I receive this error:
SERVER -> CLIENT: 220 mx.google.com ESMTP pj4sm27148656pbb.29 - gsmtp
CLIENT -> SERVER: EHLO halcyonco.io
SERVER -> CLIENT: 250-mx.google.com at your service, [68.65.121.206]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING250 SMTPUTF8
CLIENT -> SERVER: STARTTLS
SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
CLIENT -> SERVER: EHLO halcyonco.io
SERVER -> CLIENT: 250-mx.google.com at your service, [68.65.121.206]
250-SIZE 35882577250-8BITMIME
250-AUTH LOGIN PLAIN XOAUTH2 PLAIN-CLIENTTOKEN XOAUTH
250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING
250 SMTPUTF8
SMTP Error: Could not authenticate.
CLIENT -> SERVER: QUIT
SERVER -> CLIENT: 221 2.0.0 closing connection pj4sm27148656pbb.29 - gsmtp
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
I have been in touch with Namecheap as I have my hosting and domains through them but after an hour and half they could not help me.
Below is my contact.php script
<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
$name = trim($_POST["user_name"]);
$email = trim($_POST["user_email"]);
$comment = trim($_POST["comment"]);
if ($name == "" OR $email == "" OR $comment == "") {
echo '<h3>Please fill out all forms.</h3>';
exit;
}
// SPAM protection
foreach ($_POST as $value) {
if ( stripos($value, 'Content-Type') !== FALSE ) {
echo "There was a problem with the information you entered.";
exit;
}
}
//SMTP needs accurate times, and the PHP time zone MUST be set
//This should be done in your php.ini, but this is how to do it if you don't have access to that
date_default_timezone_set('America/New_York');
require '../vendor/phpmailer/phpmailer/PHPMailerAutoload.php';
//Load dependnecies from composer
//If this causes an error, run 'composer install'
require '../vendor/autoload.php';
//Create a new PHPMailer instance
$mail = new PHPMailerOAuth;
//Tell PHPMailer to use SMTP
$mail->isSMTP();
//Enable SMTP debugging
// 0 = off (for production use)
// 1 = client messages
// 2 = client and server messages
$mail->SMTPDebug = 2;
//Ask for HTML-friendly debug output
$mail->Debugoutput = 'html';
//Set the hostname of the mail server
$mail->Host = 'smtp.gmail.com';
//Set the SMTP port number - 587 for authenticated TLS, a.k.a. RFC4409 SMTP submission
$mail->Port = 587;
//Set the encryption system to use - ssl (deprecated) or tls
$mail->SMTPSecure = 'tls';
//Whether to use SMTP authentication
$mail->SMTPAuth = true;
//Set AuthType
$mail->AuthType = 'XOAUTH2';
//User Email to use for SMTP authentication - Use the same Email used in Google Developer Console
$mail->oauthUserEmail = "myemail#gmail.com";
//Obtained From Google Developer Console
$mail->oauthClientId = "1234567890.apps.googleusercontent.com";
//Obtained From Google Developer Console
$mail->oauthClientSecret = "123456789";
//Obtained By running get_oauth_token.php after setting up APP in Google Developer Console.
//Set Redirect URI in Developer Console as [https/http]://<yourdomain>/<folder>/get_oauth_token.php
// eg: http://localhost/phpmail/get_oauth_token.php
$mail->oauthRefreshToken = "1/ABCD12345EFGH6789";
//Set who the message is to be sent from
//For gmail, this generally needs to be the same as the user you logged in as
$mail->setFrom($email, $name);
//Set who the message is to be sent to
$mail->addAddress('myemail#gmail.com', 'Brandon Smith');
//Set the subject line
$mail->Subject = 'Promethean Fitness Enquiry | ' . $name;
//Read an HTML message body from an external file, convert referenced images to embedded,
//convert HTML into a basic plain-text alternative body
$mail->msgHTML = $comment;
//Replace the plain text body with one created manually
$mail->Body = $comment;
$mail->AltBody = $comment;
//Attach an image file
//send the message, check for errors
if (!$mail->send()) {
echo '<h3>Please ensure you have entered a correct email address.</h3><br>';
echo "Mailer Error: " . $mail->ErrorInfo;
} else {
header("Location: ../html/thanks.html");
exit;
}
//This is a spam protection
if ($_POST["user_address"] != "") {
echo "Your form submission has an error";
exit;
}
}
?>
Any help on what I need to do in order to fix this would be great.