html/php contact form template not sending email - php

Question

I'm using an html/php form template that I found. Every time I try to submit a completed form, I get a 405 error.
I want the submit button to send the contents of the form to my email address.
Heres the html:
<div class="col-md-6">
<form action="../assets/php/actionpage.php" name="emailform" method="POST">
<div class="row mb--20">
<div class="col-sm-6 col-md-12 col-lg-6 form-group">
<input type="text" class="form-control" placeholder="Name" />
</div>
<div class="col-sm-6 col-md-12 col-lg-6 form-group">
<input type="text" class="form-control" placeholder="E-mail" />
</div>
<div class="col-sm-6 col-md-12 col-lg-6 form-group">
<input type="text" class="form-control" placeholder="Phone" />
</div>
<div class="col-sm-6 col-md-12 col-lg-6 form-group">
<input type="text" class="form-control" placeholder="Website" />
</div>
<div class="col-12 form-group">
<textarea cols="30" rows="5" class="form-control" placeholder="Message"></textarea>
</div>
</div>
<div class="row">
<div class="col-lg-6 offset-lg-6 form-group">
<button class="btn btn-block btn--border-primary"><input type="submit" value="submit"></button>
</div>
</div>
</form>
</div>
This doesn't look out of the ordinary to me. So I think the problem is with the php.
actionpage.php:
<?php
if ( !empty($_POST) ) {}
if(!isset($_POST['submit']))
{
//This page shouldn't be accesed directly
echo "ERROR: you need to submit the form!";
exit;
}
// Collect
$name = $_POST['Name'];
$email = $_POST['E-mail'];
$phone = $_POST['Phone'];
$website = $_POST['Website'];
$message = $_POST['Message'];
// Validate
if(empty($name)||empty($email)||empty($message))
{
echo "Name, E-mail, and Message are mandatory!";
exit;
}
$email_from = $email;
$email_subject = "New Form Submission";
$email_body = "You have a new email from: $name\n their email: $email\n phone number: $phone\n and their website: $website\n Here is their message: $message";
$to = "######.##" // my email
$headers = "From $email_from \r\n";
// Send
mail($to, $email_subject, $email_body, $headers);
// redirect
header('Location: index.html');
?>
I am very new to php, so I decided to use a template.
I'm testing this using LiveServer in VScode. Is that having an impact?