PHPMailer not working on CodeIgniter - codeigniter

Question

Good evening. I've been having some trouble setting PHPMailer on my CI project. The thing is, after a lot of reading, I thought everything was settled, but no.
I'm calling the folder, outside any class, as soon as I open the php tag on my controller:
require './vendor/autoload.php';
use PHPMailer\PHPMailer\PHPMailer;
Then, inside my public function, I'm doing the following:
$mail = new PHPMailer;
$mail->isSMTP();
$mail->SMTPDebug = 5;
$mail->Host = 'smtp.gmail.com';
$mail->Port = 587;
$mail->SMTPSecure = 'tls';
$mail->SMTPAuth = true;
$mail->AuthType = 'XOAUTH2';
$mail->Username = "username";
$mail->Password = "password";
// Content //
$mail->setFrom('somemail#gmail.com');
$mail->AddReplyTo('somemail#gmail.com');
$mail->addAddress('someanothermail#gmail.com', 'Contacto');
$mail->Subject = 'This is the subject';
$mail->Body = 'This is the message';
if (!$mail->send()) {
echo "Mailer Error: " . $mail->ErrorInfo;
} else {
echo "Awesome sauce!";
}
So, here's what the debugger says:
2017-11-28 14:24:37 Connection: opening to smtp.gmail.com:587, timeout=300, options=array()
2017-11-28 14:24:38 Connection: opened
2017-11-28 14:24:38 SMTP INBOUND: "220 smtp.gmail.com ESMTP d15sm21670245qkc.26 - gsmtp"
2017-11-28 14:24:38 SERVER -> CLIENT: 220 smtp.gmail.com ESMTP d15sm21670245qkc.26 - gsmtp
2017-11-28 14:24:38 CLIENT -> SERVER: EHLO localhost
2017-11-28 14:24:38 SMTP INBOUND: "250-smtp.gmail.com at your service, [190.104.220.99]"
2017-11-28 14:24:38 SMTP INBOUND: "250-SIZE 35882577"
2017-11-28 14:24:38 SMTP INBOUND: "250-8BITMIME"
2017-11-28 14:24:38 SMTP INBOUND: "250-STARTTLS"
2017-11-28 14:24:38 SMTP INBOUND: "250-ENHANCEDSTATUSCODES"
2017-11-28 14:24:38 SMTP INBOUND: "250-PIPELINING"
2017-11-28 14:24:38 SMTP INBOUND: "250-CHUNKING"
2017-11-28 14:24:38 SMTP INBOUND: "250 SMTPUTF8"
2017-11-28 14:24:38 SERVER -> CLIENT: 250-smtp.gmail.com at your service, [190.104.220.99]250-SIZE 35882577250-8BITMIME250-STARTTLS250-ENHANCEDSTATUSCODES250-PIPELINING250-CHUNKING250 SMTPUTF8
2017-11-28 14:24:38 CLIENT -> SERVER: STARTTLS
2017-11-28 14:24:39 SMTP INBOUND: "220 2.0.0 Ready to start TLS"
2017-11-28 14:24:39 SERVER -> CLIENT: 220 2.0.0 Ready to start TLS
2017-11-28 14:24:39 Connection failed. Error #2: stream_socket_enable_crypto(): SSL operation failed with code 1. OpenSSL Error messages:error:14090086:SSL routines:ssl3_get_server_certificate:certificate verify failed [C:\xampp\htdocs\crm\vendor\phpmailer\phpmailer\src\SMTP.php line 403]
SMTP Error: Could not connect to SMTP host.
2017-11-28 14:24:39 CLIENT -> SERVER: QUIT
2017-11-28 14:24:39
2017-11-28 14:24:39
2017-11-28 14:24:39
2017-11-28 14:24:39 Connection: closed
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Mailer Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
Any suggestions?