PHP邮件程序收到电子邮件时出错

Question

我正在使用下面的代码作为我正在处理的网站的邮件列表，并且它在我的本地主机上使用我的凭据正常工作，并在其他服务器上使用其他一些凭据给我。

<?php
if(isset($_POST['submit']))
{
    require("class.phpmailer.php");
    $mail = new PHPMailer();                       
    $query = "SELECT * FROM mailing_list";
    $result = mysqli_query($connect, $query)    
    or die('Error querying the database!');

    $mail->IsSMTP();  
    $mail->Host= "smtp"; 
    $mail->Username= "some email address was given to me"; 
    $mail->Password= "password"; 
    $mail->SMTPAuth= true;
    $mail->SMTPSecure = 'tls';
    $mail->From ="some email address was given to me";
    $mail->FromName ="CSCA";

    while($row = mysqli_fetch_array($result))
    {

    $first_name = $row['first_name'];
    $last_name = $row['last_name'];
    $to = $row['email'];
    $mail->ClearAddresses();        
    $mail->AddAddress($to);         
            $mail->Subject= $_POST['subject'];

        $mail->Body = "Dear $first_name $last_name,\n" . $_POST['body'];
        $mail->WordWrap = 50;

        if(!$mail->Send()) 
        {
            echo 'Message was not sent.';
            echo 'Mailer error: ' . $mail->ErrorInfo;
        }   

现在，当我在同一网站的联系我们页面中使用以下代码时，使用我自己的凭据可以很好地使用我的本地主机，但它不能在我上面使用的其他服务器上运行。我在垃圾邮件中收到了一条邮件，邮件传递失败了＃39;我不知道如何使用相同的凭据发送邮件，但您无法收到！我的意思是使用相同的服务器和相同的凭据，您的邮件列表工作正常，但联系我们表单给出错误。有办法解决这个问题吗？

提前致谢！

<?php
    require("class.phpmailer.php");
    $mail = new PHPMailer();     

    $name = $_REQUEST['name'];
    $email = $_REQUEST['email'] ;
    $message = $_REQUEST['message'] ;

    $mail->IsSMTP();  
    $mail->Host="smtp"; 
    $mail->Username="some email address was given to me"; 
    $mail->Password="password"; 
    $mail->SMTPAuth=true;
    $mail->SMTPSecure = 'tls'; 
    $mail->From =$email;
    $mail->FromName =$name; 
    $mail->AddAddress("some email address was given to me", "Some name");

    $mail->IsHTML(true);

    $mail->Subject = "You have received feedback from your website!";


    $mail->Body    = $message;
    $mail->AltBody = $message;

    if(!$mail->Send())
    {
      echo "Message could not be sent. <p>";
      echo "Mailer Error: " . $mail->ErrorInfo;
      exit;
    }