javascript - Error message with php from HTML form submission

I'm using this form in an HTML page and it works on 2 sites. I've copied the code below to create contact.html and contact.php

I've tried for 2 days to get this to work on a new site and keep getting an error message:

Warning: Unexpected character in input: '\' (ASCII=92) state=1 in D:\Hosting\7131065\html\contact.php on line 31

Along with the response from the PHP:
Contact form successfully submitted.

Yet the '\' does not throw and error on other sites. Removing '\' results in a different error.

The response should appear (via AJAX) in contact.html but instead the response is displaying page contact.php

HTML form (including links)

CSS 

    
    
    
    
    
    

HTML

                    


                    

                        

                            

                                

                                    
                                    
                                
                                

                            
                            


                                

                                    
                                    
                                
                                

                            
                    

                    How did you hear about us?                                                                                       
                    
                          Please click to make selection

                          Web Search
                          Facebook
                          Friend
                          Support Group
                          Print Ad
                          Bar
                          Other
                        
                    
                    


                        

                            
                        
                        

                    
                        
                    
                      
                
JS


    
    

    

contact.php

// Set up

$from = 'new-contact@tsagl.org/';
$sendTo = 'contact-manager@tsagl.org';
$subject = 'New message from Conact page';
$fields = array('yourname' => 'Name', 'email' => 'Email', 'hear' => 'How did you hear about us?', 'message' => 'Message'); 
$okMessage = 'Contact form successfully submitted.';
$errorMessage = 'There was an error while submitting the form. Please try again later';

// Actions

if (empty($_POST['message'])) {

    exit;
}

try
{
    $emailText = "New message from Contact Page\n___________________________\n";

    foreach ($_POST as $key => $value) {

        if (isset($fields[$key])) {

            $emailText .= "$fields[$key]: $value\n";
        }
    }

    mail($sendTo, $subject, $emailText, "From: " . $from);

    $responseArray = array('type' => 'success', 'message' => $okMessage);
}
catch (\Exception $e)
{

    $responseArray = array('type' => 'danger', 'message' => $errorMessage);
}

if (!empty($_SERVER['HTTP_X_REQUESTED_WITH']) && strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest') {
    $encoded = json_encode($responseArray);

    header('Content-Type: application/json');

    echo $encoded;
}

else {
    echo $responseArray['message'];
}

Any response greatly appreciated!