Contact form won't send to email

Question

I've done this contact form loads of times and it works fine but for some reason this particular form won't send to email. The php is good so it must be my form. I'll put both bits of code up anyway. Thanks
PHP:
<?php
if ($_POST){
if (!filter_input(INPUT_POST, 'email', FILTER_VALIDATE_EMAIL)){
$message="Please provide a correct email address";} else {
  $name = strip_tags($_POST['name']);
  $company_name = strip_tags($_POST['company_name']);
  $telephone = strip_tags($_POST['telephone']);
  $email = $_POST['email'];
  $comments = strip_tags($_POST['comments']);
  $to = '[email protected]';
  $subject = 'Contact form submitted.';
  $body = $name. "\n". $company_name. "\n". $telephone. "\n". $email. "\n" .$comments;
  $headers = 'From: ' .$email;
  if (mail($to, $subject, $body, $headers)) {
  echo 'Thanks for contacting us. We\'ll be in touch soon!';
  } else {
  $message = 'Sorry an error occurred. Please try again later.';
?>
<?php echo "<p style='color:red'>$message</p>"; ?>
HTML:
<form id="contactform" action="" method="post">
<p>Name:<br/><input name="name" type="text" required /></p>
<p>Company Name: <br/><input name="company_name" type="text" required/></p>
<p>Telephone: <br/><input name="telephone" type="tel" required/></p>
<p>Email: <br/><input name="email" type="email" required/></p>
<p>Comments: <br/><textarea name="comments" required/>   </textarea></p>
    <input type="submit" name="submit" value="Send!" formmethod="post"/>
</form>

Answer 1

PEAR is a library of useful functions that is often included in a PHP installation.
BUT. . .PHP only uses the mail capabilities of the server. If the server doesn't allow it, then you may not able to send email no matter what. . .however, I am not absolutely sure of that. I have never had to work with a server that did not support mail.
SMTP is a protocol that uses an email account to send mail. You may be able to tie your mail to an external SMTP account, for instance even a GMAIL account. PHPMailer is an add-on that you can use to do this. You can install it on your website. It isn't hard to use, but it is more involved than simply using PHP mail().
But really, have a conversation with the server admin about all of this. Find out why PHP mail isn't installed, and if he is willing to install it.