Cannot POST /.php file when submitting form for email - php

Question

I'm trying to get a HTML from to work together with PHP in order to make a form for sending a mail, but after submitting the form, PHP file is saying
Cannot POST /quotation.php
Here is my HTML code
<div id="quotation" class="reveal-modal" data-reveal>
<a class="close-reveal-modal">×</a>
<h3>Request Quotation</h3>
<p>Please fill out this information and we will contact you as soon as possilble.</p>
<form method="post" name="" action="quotation.php">
<div class="row">
<div class="large-6 columns">
<label>Name
<input type="text" name="name" placeholder="Name" />
</label>
</div>
<div class="large-6 columns">
<label>Lastname
<input type="text" name="lastname" placeholder="Lastname" />
</label>
</div>
</div>
<div class="row">
<div class="large-6 columns">
<label>Company name
<input type="text" name="company" value="" placeholder="Your company">
</label>
</div>
<div class="large-6 columns">
<label>E-mail
<input type="text" name="email" value="" placeholder="E-mail">
</label>
</div>
</div>
<div class="row">
<div class="large-12 columns">
<label>Additional details
<textarea name="message" placeholder="Additional details here"></textarea>
</label>
</div>
</div>
<input class="button radius" type="submit" name='submit' value="submit">
</form>
</div>
And this is the PHP that runs the form
<?php
if(!isset($_POST['submit']))
{
//This page should not be accessed directly. Need to submit the form.
echo "error; you need to submit the form!";
}
$name = $_POST['name'];
$lastname = $_POST['lastname'];
$company = $_POST['company'];
$visitor_email = $_POST['email'];
$message = $_POST['message'];
$email_from = $visitor_email;//<== update the email address
$email_subject = "New Form submission";
$email_body = "You have received a new message from the user $name, $lastname.\n".
"Here is the message:\n $message".
$to = "email#gmail.com";
$headers = "From: $email_from \r\n";
$headers .= "Reply-To: $visitor_email \r\n";
//Send the email!
mail($to,$email_subject,$email_body,$headers);
echo "Mail Sent. Thank you " . $name . ", we will contact you shortly.";
alert("yo");
//done. redirect to thank-you page.
header('Location: index.html');
?>
I added alert and echo for submit button, but none of them appears so looks like PHP is not even running.
It would be great if someone could guide me trough this problem or point out what am I doing wrong.