如果您正在使用SMTP配置来发送电子邮件，请尝试使用PHPMailer。您可以从https://github.com/PHPMailer/PHPMailer下载该库。

我用这种方式创建了我的电子邮件:

function send_mail($email, $recipient_name, $message='')
{
    require("phpmailer/class.phpmailer.php");

    $mail = new PHPMailer();

    $mail->CharSet = "utf-8";
    $mail->IsSMTP();                                      // Set mailer to use SMTP
    $mail->Host = "mail.example.com";  // Specify main and backup server
    $mail->SMTPAuth = true;     // Turn on SMTP authentication
    $mail->Username = "myusername";  // SMTP username
    $mail->Password = "p@ssw0rd"; // SMTP password

    $mail->From = "me@walalang.com";
    $mail->FromName = "System-Ad";
    $mail->AddAddress($email, $recipient_name);

    $mail->WordWrap = 50;                                 // Set word wrap to 50 characters
    $mail->IsHTML(true);                                  // Set email format to HTML (true) or plain text (false)

    $mail->Subject = "This is a Sampleenter code here Email";
    $mail->Body    = $message;
    $mail->AltBody = "This is the body in plain text for non-HTML mail clients";
    $mail->AddEmbeddedImage('images/logo.png', 'logo', 'logo.png');
    $mail->addAttachment('files/file.xlsx');

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

    echo "Message has been sent";
}

这可能是一个问题，“From:”$电子邮件地址在这部分的$头:

From: \"$name\" <$email>

尝试一下，发送一封没有标题部分的电子邮件，比如:

mail('user@example.com', $subject, $message); 

如果是这种情况，请尝试使用在您试图从中发送邮件的系统中已经创建的电子邮件帐户。

总是尝试在邮件函数中发送标题。 如果您通过localhost发送邮件，则执行SMTP设置以发送邮件。 如果您通过服务器发送邮件，请检查您的服务器上是否启用了电子邮件发送功能。

以我为例，这封电子邮件发送得很好，但却很难收到，因为整个信息在一行中超过998个字符。我需要使用以下行使最大长度为70的行:wordwrap($email_message, 70， "\r\n");。

https://www.rfc-editor.org/rfc/rfc5322#section-2.1.1

该规范对一行中的字符数量有两个限制。每行字符必须不超过998个字符，不超过78个字符，不包括CRLF字符。

在邮件功能中添加邮件头。

$header = "From: noreply@example.com\r\n";
$header.= "MIME-Version: 1.0\r\n";
$header.= "Content-Type: text/html; charset=ISO-8859-1\r\n";
$header.= "X-Priority: 1\r\n";

$status = mail($to, $subject, $message, $header);

if($status)
{
    echo '<p>Your mail has been sent!</p>';
} else {
    echo '<p>Something went wrong. Please try again!</p>';
}

你可以通过以下方法查看错误:

error_reporting(E_ALL);

我的示例代码是:

<?php
    use PHPMailer\PHPMailer\PHPMailer;
    require 'PHPMailer.php';
    require 'SMTP.php';
    require 'Exception.php';

    $name = $_POST['name'];
    $mailid = $_POST['mail'];
    $mail = new PHPMailer;
    $mail->IsSMTP();
    $mail->SMTPDebug = 0;                   // Set mailer to use SMTP
    $mail->Host = 'smtp.gmail.com';         // Specify main and backup server
    $mail->Port = 587;                      // Set the SMTP port
    $mail->SMTPAuth = true;                 // Enable SMTP authentication
    $mail->Username = 'someone@gmail.com';  // SMTP username
    $mail->Password = 'password';           // SMTP password
    $mail->SMTPSecure = 'tls';              // Enable encryption, 'ssl' also accepted

    $mail->From = 'someone@gmail.com';
    $mail->FromName = 'name';
    $mail->AddAddress($mailid, $name);       // Name is optional
    $mail->IsHTML(true);                     // Set email format to HTML
    $mail->Subject = 'Here is the subject';
    $mail->Body    = 'Here is your message' ;
    $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';
    if (!$mail->Send()) {
       echo 'Message could not be sent.';
       echo 'Mailer Error: ' . $mail->ErrorInfo;
       exit;
    }
    echo 'Message has been sent';
?>