PHP Email Form适用于某些人，而不适用于其他人。我是否需要添加SMTP服务器

Question

我的网站上有一个表单，使用PHP脚本将消息通过电子邮件发送到我的Gmail。每次我测试它，它工作，我收到电子邮件。但我还有其他几个人在测试表格 - 而且电子邮件从未通过。我是否需要配置SMTP服务器？我已经阅读了一些文章 - 但对于如何使代码适应我当前的PHP文件而感到困惑。任何帮助非常感谢！

FORM.PHP

  <? php
  // Define some constants
define("RECIPIENT_NAME", "MY NAME");
define("RECIPIENT_EMAIL", "MY GMAIL ADDRESS");
define("EMAIL_SUBJECT", "Website Enquiry");

$full_name;
$email;
$subject;
$message;
$captcha;
if (isset($_POST['name'])) {
  $name = $_POST['name'];
  if ($name != filter_var($name, FILTER_SANITIZE_STRING)) {
    echo "Name is not valid!";
    exit; // or exit w/e you please
  }
} else {
  echo "Name field is required!";
  exit; // or exit w/e you please
}
if (isset($_POST['email'])) {
  $email = $_POST['email'];
  if (!filter_var($email, FILTER_VALIDATE_EMAIL)) {
    echo "Email is not valid!";
    exit; // or exit w/e you please
  }
} else {
  echo "Email field is required!";
  exit; // or exit w/e you please
}

if (isset($_POST['message'])) {
  $message = $_POST['message'];
  if ($message != filter_var($message, FILTER_SANITIZE_STRING)) {
    echo "Message is not valid!";
    exit; // or exit w/e you please
  }
} else {
  echo "Message field is required!";
  exit; // or exit w/e you please
}

if (isset($_POST['g-recaptcha-response'])) {
  $captcha = $_POST['g-recaptcha-response'];
}

if (!$captcha) {
  echo 'error';
  exit;
}

$response = file_get_contents("https://www.google.com/recaptcha/api/siteverify?INSERT GOOGLE VERIFICATION KEY&response=".$captcha.
  "&remoteip=".$_SERVER['REMOTE_ADDR']);

if ($response.success == false) {
  echo 'fail';
  // No need to exit() here, code ends after this anyway
} else {
  // If all values exist, send the email
  if ($name && $email && $message) {
    $recipient = RECIPIENT_NAME.
    " <".RECIPIENT_EMAIL.
    ">";
    $headers = "From: ".$name.
    " <".$email.
    ">";
    $success = mail($recipient, EMAIL_SUBJECT, $message, $headers);
    echo "success";
  } else {
    echo "Name, email and message are required!";
  }
  // No need to exit() here, code ends after this anyway
} ?>

/*HTML*/

<p><b>CONTACT FORM</b>
</p>
<form role="form" id="form" action="form.php" method="post">
  <div class="form-group">
    <label for="name">Your Name</label>
    <input type="text" class="form-control" id="name" name="name" placeholder="Enter name">

    <span class="help-block" style="display: none;">Please enter your name.</span>

    <label for="email">Email address</label>
    <input type="email" class="form-control" id="email" name="email" placeholder="Enter email">
    <span class="help-block" style="display: none;">Please enter a valid e-mail address.</span>

    <label for="message">Message</label>
    <textarea class="form-control" rows="7" id="message" name="message" placeholder="Enter message"></textarea>

    <span class="help-block" style="display: none;">Please enter a message.</span>
  </div>
  <div class="form-group">
    <div class="g-recaptcha" data-theme="dark" data-sitekey="INSERT DATA SITE KEY HERE"></div>
    <span class="help-block" style="display: none;">Please check that you are not a robot.</span>
  </div>
  <button type="submit" id="Submit" data-loading-text="Sending..." class="btn btn-default">Send Message</button>
</form>

</div>

我解决了问题是$ email。如果用户使用某些电子邮件，如@ gmail.com或@ hotmail.com，则不会发送电子邮件。因此，我调整了我的PHP以使用我的虚拟主机电子邮件作为“FROM”地址 - 并在电子邮件的消息部分中发布了NAME，EMAIL和MESSAGE。我现在收到的电子邮件无论用户的电子邮件地址如何。这是修改后的PHP：

<?php
// Define some constants
define( "RECIPIENT_NAME", "INSERT NAME" );
define( "RECIPIENT_EMAIL", "INSERT MY GMAIL" );
define( "EMAIL_SUBJECT", "Website Enquiry" );
define( "SENT_FROM", "Pauls Website" );
define( "SENT_EMAIL", "INSERT MY WEBHOST EMAIL" );

$full_name;$email;$subject;$message;$captcha;
if(isset($_POST['name']))
{
	$name=$_POST['name'];
	if($name = htmlspecialchars($name, ENT_QUOTES));
    if($name != filter_var($name, FILTER_SANITIZE_STRING))
    {
        echo "Name is not valid!";
        exit; // or exit w/e you please
    }
}
else
{
    echo "Name field is required!";
    exit; // or exit w/e you please
}
if(isset($_POST['email']))
{
    $email=$_POST['email'];
	if($email = htmlspecialchars($email, ENT_QUOTES));
    if(! filter_var($email, FILTER_VALIDATE_EMAIL))
    {
        echo "Email is not valid!";
        exit; // or exit w/e you please
    }
}
else
{
    echo "Email field is required!";
    exit; // or exit w/e you please
}

if(isset($_POST['message']))
{
	$message =$_POST['message']; 
	 if($message = htmlspecialchars($message, ENT_QUOTES));
    if($message != filter_var($message, FILTER_SANITIZE_STRING))
	
    {
        echo "Message is not valid!";
        exit; // or exit w/e you please
    }
}
else
{
    echo "Message field is required!";
    exit; // or exit w/e you please
}

$body = "<b>Name:</b> " .$name. "<br/><b>Email:</b> " .$email. "<br/><b>Message:</b> " .$_POST["message"];

if(isset($_POST['g-recaptcha-response']))
{
    $captcha=$_POST['g-recaptcha-response'];
}

if(!$captcha)
{
    echo 'error';
    exit;
}

$response=file_get_contents("https://www.google.com/recaptcha/api/siteverify?INSERT SECRET CODE&response=".$captcha."&remoteip=".$_SERVER['REMOTE_ADDR']);

if($response.success==false)
{
    echo 'fail';
    // No need to exit() here, code ends after this anyway
}
else
{
    // If all values exist, send the email
    if ( $name && $email && $message ) 
    {
		$headers  = 'MIME-Version: 1.0' . "\r\n";
		$headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";
		$headers .= "From: " . SENT_FROM . " <" . SENT_EMAIL . ">"; 
		$recipient = RECIPIENT_NAME . " <" . RECIPIENT_EMAIL . ">";	
        $success = mail( $recipient, EMAIL_SUBJECT, $body, $headers );
        echo "success";
    }
    else
    {
        echo "Name, email and message are required!";
    }
    // No need to exit() here, code ends after this anyway
}
?>

我还添加了一些代码，以便在表单中接受撇号，并在收到的电子邮件中正确显示。只是试图找出如何实现nl2br（），以便消息包含任何新行。目前它将消息截断为一行，即使用户有多个段落的新行。