I'm developing a kind of simple form for a side project I am doing.
It's based on a very simple contact form.
I have a very similar one working here
But the one here doesn't appear to be working
https://crgdev.com/BrandAddition/
Code below (very new to the site so probably doing something wrong)
<?php
if(isset($_POST['email'])) {
    // EDIT THE 2 LINES BELOW AS REQUIRED
    $email_to = "chris@crgdev.com";
    $email_subject = "New Starter - ";
    function died($error) {
        // your error code can go here
        echo "We are very sorry, but there were error(s) found with the form you submitted. ";
        echo "These errors appear below.<br /><br />";
        echo $error."<br /><br />";
        echo "Please go back and fix these errors.<br /><br />";
        die();
    }
    // validation expected data exists
    if(!isset($_POST['first_name']) ||
       !isset($_POST['last_name']) ||
       !isset($_POST['email']) ||
       !isset($_POST['accessrequirements'])) {
        died('We are sorry, but there appears to be a problem with the form you submitted.');
    }
    $first_name = $_POST['first_name']; // required
    $last_name = $_POST['last_name']; // required
    $email_from = $_POST['email']; // required
    $accessrequirements = $_POST['accessrequirements']; // required
    $error_message = "";
    $email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';
    if(!preg_match($email_exp,$email_from)) {
        $error_message .= 'The Email Address you entered does not appear to be valid.<br />';
    }
    $string_exp = "/^[A-Za-z .'-]+$/";
    if(!preg_match($string_exp,$first_name)) {
        $error_message .= 'The First Name you entered does not appear to be valid.<br />';
    }
    if(!preg_match($string_exp,$last_name)) {
        $error_message .= 'The Last Name you entered does not appear to be valid.<br />';
    }
    if(strlen($accessrequirements) < 2) {
        $error_message .= 'The Comments you entered do not appear to be valid.<br      />';
    }
    if(strlen($error_message) > 0) {
        died($error_message);
    }
    $email_message = "Form details below.\n\n";
    function clean_string($string) {
        $bad = array("content-type","bcc:","to:","cc:","href");
        return str_replace($bad,"",$string);
    }
    $email_message .= "First Name: ".clean_string($first_name)."\n";
    $email_message .= "Last Name: ".clean_string($last_name)."\n";
    $email_message .= "Start Date: ".clean_string($start_date)."\n";
    $email_message .= "Job Title: ".clean_string($job_title)."\n";
    $email_message .= "Team Leader: ".clean_string($team_leader)."\n";
    $email_message .= "Location: ".clean_string($location)."\n";
    $email_message .= "Access Requirements: ".clean_string($accessrequirements)."\n";
    $email_message .= "Email/Phone Access: ".clean_string($emailaccess)."\n";
    $email_message .= "Other Requirements: ".clean_string($otherrequirements)."\n";
    $email_message .= "Subitted by: ".clean_string($email_from)."\n";
    // create email headers
    $headers = 'From: '.$email_from."\r\n".
               'Reply-To: '.$email_from."\r\n" .
               'X-Mailer: PHP/' . phpversion();
     @mail($email_to, $email_subject, $email_message, $headers);
?>
 <!-- include your own success html here -->
Thank you for submitting your New STarter Form. We will be in touch with you    regarding any updates.
<html>
<p>Go back to <a href="https://brandaddition.com">Brand Addition/a></p>
</html>
<style>
body {
    font-size: larger;
    text-align: center;
 }
</style>
<?php
}
?>
<body>
<div class="fixedwidth">
<div id="brandlogo"><img src="brandadditionlogo.png"</div>
<h1>New Starter Form</h1>
<div id="formdiv">
<form name="newstarterform" method="post" action="send_form_email.php">
<table id="formtable">
 <tr>
   <td><input  type="text" name="first_name" placeholder="First Name" maxlength="50"></td>
 </tr>
 <tr>
   <td><input  type="text" name="last_name" placeholder="Last Name" maxlength="50"></td>
 </tr>
 <tr>
    <td>Start Date: <input type="date" name="start_date" placeholder="Start Date" maxlength="50"></td>
 </tr>
 <tr>
    <td><input type="text" name="job_title" placeholder="Job Title" maxlength="50"></td>
 </tr>
 <tr>
    <td><input type="text" name="team_leader" placeholder="Team Leader" maxlength="50"></td>
 </tr>
 <tr>
    <td> Location:
        <select name="location">
        <option value="Manchester">Manchester</option>
        <option value="London">London</option>
        <option value="Ireland">Ireland</option>
        </select>
    </td>
 </tr>
 <tr>
   <td>
    <p class="pagepara"><span class="bold">List the access requirements needed, this should include</span><br><br>
      • Level of oasis access or which user we should copy to set the oasis access level<br>
      • Corporate programs that the user should have access to<br>
      • Any specific applications that the employee would need access to<br>
      • Which share drive folders should the employee have access to<br>
    </p>
    <textarea name="accessrequirements" placeholder="Access Requirements" maxlength="1000" cols="50" rows="10"></textarea>
   </td>
 </tr>
 <tr>
   <td>
    <p class="pagepara"><span class="bold">List the email and telephone groups that the user should receive<br> communications from</span><br><br>
    </p>
    <textarea name="emailaccess" placeholder="Email/Phone Access" maxlength="1000" cols="50" rows="10"></textarea>
   </td>
 </tr>
 <tr>
   <td>
     <input type="checkbox" name="desktop computer">Desktop Computer
     <input type="checkbox" name="laptop">Laptop <br>
     <input type="checkbox" name="mobile phone">Mobile phone
     <input type="checkbox" name="remote access">Remote Access<br><br>
     <textarea name="otherrequirements" placeholder="Other requirements not mentioned above?" maxlength="1000" cols="50" rows="10"></textarea>
   </td>
 </tr>
 <tr>
   <td>
     <p class="bold">Enter your email below for communications</p>
     <input type="email" name="submitter">
   </td>
 </tr>
 <tr>
   <td style="padding: 40px 0px 80px 0px">
     <input type="submit" value="Submit">
   </td>
  </tr>
  </table>
  </form>
</div>
 <div id="blueline"></div>
</div>
</body>
 
    