无法使用php

Question

我正在尝试通过PHP使用我的Gmail帐户详细信息发送SMTP电子邮件，但每次尝试都会出错。我正在编写代码，以便您可以看到问题所在。

PHP：

<?php

        require 'phpmailer/PHPMailerAutoload.php';

        $mail = new PHPMailer;
        //Enable SMTP debugging. 
        $mail->SMTPDebug = 3;                               
        //Set PHPMailer to use SMTP.
        $mail->isSMTP();            
        //Set SMTP host name                          
        $mail->Host = "smtp.gmail.com";
        //Set this to true if SMTP host requires authentication to send email
        $mail->SMTPAuth = true;                          
        //Provide username and password     
        $mail->Username = "username";                 
        $mail->Password = "password";                           
        //If SMTP requires TLS encryption then set it
        $mail->SMTPSecure = "tls";                           
        //Set TCP port to connect to 
        $mail->Port = 587;                                   

        $mail->From = "sender email";
        $mail->FromName = "sender name";

        $mail->addAddress("receiver email");

        $mail->isHTML(true);

        $mail->Subject = "Subject Text";
        $mail->Body = "<i>Mail body in HTML</i>";
        $mail->AltBody = "This is the plain text version of the email content";

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

和我面临的错误：

2016-08-12 00:22:02 Connection: opening to smtp.gmail.com:587, 
timeout=300, options=array ( ) 2016-08-12 00:22:16 SMTP ERROR: Failed to 
connect to server: Network is unreachable (101) 2016-08-12 00:22:16 SMTP 
connect() failed. Mailer Error: SMTP connect() failed. 

任何帮助将不胜感激。 谢谢