以下“发件人"地址失败，但未连接，但调用了Mail()

大家好，我收到此错误:

Hello guys I get this error:

以下发件人地址失败:username_from@gmail.com:未连接就调用Mail()

The following From address failed: username_from@gmail.com : Called Mail() without being connected

<?php
require("PHPMailer/class.phpmailer.php");

$msg = 'hello world!';

$mail = new PHPMailer();
$mail->IsSMTP();
$mail->Host = 'smtp.gmail.com';
$mail->Port = 465;
$mail->SMTPAuth = true;
$mail->Username = 'username@gmail.com';
$mail->Password = 'password';
$mail->SMTPSecure = 'ssl';
$mail->From = 'username_from@gmail.com';
$mail->FromName = 'My name';
$mail->AddAddress('other_user@gmail.com', '');
$mail->WordWrap = 50;
$mail->IsHTML(true);
$mail->Subject = 'hello';
$mail->Body = $msg;

if(!$mail->Send()){
    echo "Mailer Error: " . $mail->ErrorInfo;
}
else{
    echo "Message has been sent";
}
?>

我该如何解决?谢谢！我使用Gmail邮件服务器从在PHP中运行XAMPP的本地主机发送电子邮件.

How can I fix it? Thanks! I send email from localhost running XAMPP in PHP using Gmail mail server.