PHP和Ajax表单发送电子邮件但电子邮件未发送[重复]

I send email from my website using HTML and Ajax, the email is sent sometimes but 90% of the time it doesn't deliver. the messages are not even in the email's spam. this is my code I have it on my website for about 2 years but i never tought it's not working please help :

html :

       <form id="contact-form" class="contact-form" action="#">
            <p class="contact-name">
                <input id="contact_name" type="text" placeholder="Full Name" value="" name="name" />
            </p>
            <p class="contact-email">
                <input id="contact_email" type="text" placeholder="Email Address" value="" name="email" />
            </p>
            <p class="contact-message">
                <textarea id="contact_message" placeholder="Your Message" name="message" rows="10" cols="40"></textarea>
            </p>
            <p class="contact-submit">
                <a id="contact-submit" class="submit" href="#">Send Your Email</a>
            </p>

            <div id="response">

            </div>
        </form>

Ajax (fichier main.js):

$("#contact-submit").on('click',function() {
    $contact_form = $('#contact-form');

    var fields = $contact_form.serialize();

    $.ajax({
        type: "POST",
        url: "http://musamr.com/wp-content/themes/musamr/include/php/contact.php",
        data: fields,
        dataType: 'json',
        success: function(response) {

            if(response.status){
                $('#contact-form input').val('');
                $('#contact-form textarea').val('');
            }

            $('#response').empty().html(response.html);
        }
    });
    return false;
});

contact.php

<?php
/*
* Contact Form Class
*/
header('Cache-Control: no-cache, must-revalidate');
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Content-type: application/json');

$admin_email = 'monemail@gmail.com'; // Your Email
$message_min_length = 5; // Min Message Length

class Contact_Form{
    function __construct($details, $email_admin, $message_min_length){

        $this->name = stripslashes($details['name']);
        $this->email = trim($details['email']);
        $this->subject = 'Contact from Your Website'; // Subject 
        $this->message = stripslashes($details['message']);

        $this->email_admin = $email_admin;
        $this->message_min_length = $message_min_length;

        $this->response_status = 1;
        $this->response_html = '';
    }

    private function validateEmail(){
        $regex = '/^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i';

        if($this->email == '') { 
            return false;
        } else {
            $string = preg_replace($regex, '', $this->email);
        }

        return empty($string) ? true : false;
    }

    private function validateFields(){
        // Check name
        if(!$this->name)
        {
            $this->response_html .= '<p>Please enter your name</p>';
            $this->response_status = 0;
        }

        // Check email
        if(!$this->email)
        {
            $this->response_html .= '<p>Please enter an e-mail address</p>';
            $this->response_status = 0;
        }

        // Check valid email
        if($this->email && !$this->validateEmail())
        {
            $this->response_html .= '<p>Please enter a valid e-mail address</p>';
            $this->response_status = 0;
        }

        // Check message length
        if(!$this->message || strlen($this->message) < $this->message_min_length)
        {
            $this->response_html .= '<p>Please enter your message. It should have at least '.$this->message_min_length.' characters</p>';
            $this->response_status = 0;
        }
    }

    private function sendEmail(){
        $mail = mail($this->email_admin, $this->subject, $this->message,
             "From: ".$this->name." <".$this->email.">
"
            ."Reply-To: ".$this->email."
"
        ."X-Mailer: PHP/" . phpversion());

        if($mail)
        {
            $this->response_status = 1;
            $this->response_html = '<p>Thank You!</p>';
        }
    }

    function sendRequest(){
        $this->validateFields();
        if($this->response_status)
        {
            $this->sendEmail();
        }

        $response = array();
        $response['status'] = $this->response_status;   
        $response['html'] = $this->response_html;

        echo json_encode($response);
    }
}

$contact_form = new Contact_Form($_POST, $admin_email, $message_min_length);
$contact_form->sendRequest();

?>

</div>

The mail function is extremely unreliable. You should consider using a SMTP server & a library like PHPMAILER to make integration easier.

phpmailer: https://github.com/PHPMailer/PHPMailer

The mail function will attempt to send but more times than not it will go into the users spam folder or the destination may reject it.

Also instead of that regex you can use filter_var('bob@example.com', FILTER_VALIDATE_EMAIL)