PHPMailer不提供错误消息或仅发送白色屏幕的电子邮件

I am trying to send emails using PHP mailer. Nothing happens all I get is a white screen in the web browser. I have used different examples of code changed ssl to tls port 587 to 465 used require the autoload.php phpmailer.php smtp.php anything I can find to get an indication as to where the problem is. The code is exactly the same as the one on https://subinsb.com/send-mails-via-smtp-server-gmail-outlook-php apart from the email credentials etc. Any ideas you may have or if you see something I don't would be appreciated.

<?php
$account = "xxxxxxxxx@gmail.com";
$password = 'xxxxxx';
$from = 'xxxxxxxx@gmail.com';
$from_name = 'Adam Johnson';
$subject = 'Test';
$msg = 'This is a test';
$to = "xxxxxxxxx@hotmail.com";

require ('/PHPMailer/class.phpmailer.php');

$mail->SMTPDebug = 3;
$mail = new PHPMailer();
$mail->isSMTP();
$mail->CharSet = 'UTF-8';
$mail->Host = 'smtp.gmail.com';
$mail->SMTPAuth = true;
$mail->Port = 587;
$mail->Username = $account;
$mail->Password = $password;
$mail->SMTPSecure = 'tls';
$mail->From = $from;
$mail->FromName = $from_name;
$mail->isHTML(true);
$mail->Subject = $subject;
$mail->Body = $msg;
$mail->addAddress($to);

if (!mail->send()){
echo 'Mailer Error: ' . $mail->ErrorInfo;
}
else {
echo 'Message sent!';
}
?>

this

require ('/PHPMailer/class.phpmailer.php');

$mail->SMTPDebug = 3;
$mail = new PHPMailer();

should look like this;

require ('/PHPMailer/class.phpmailer.php');

$mail = new PHPMailer();
$mail->SMTPDebug = 3;

You've not initialed the $mail variable yet in your code, yet you're trying to set $mail->SMTPDebug = 3; on an non existent object.

EDIT

One more typo in the code. The line if (!mail->send()){ is missing the $ variable declaration. Make sure it reads if (!$mail->send()){