Q:

"Start tag head seen but an element of the same type was already open"

When I try my website on the W3C Validator, I have this error: 

Start tag head seen but an element of the same type was already open.

I tried many things like: re-encode in UTF-8 without BOM, change the syntax, put in and out differents meta but it doesnt resolve my problem.
Here is my code: 
<?php if($_SERVER['REQUEST_URI'] == '/index.php') header('Location:/')?>

<!DOCTYPE html>
<html lang="fr">   
<!-- Begin Cookie Consent plugin -->
<script type="text/javascript">
    window.cookieconsent_options = {"message":"En poursuivant votre navigation sur ce site, vous acceptez l’utilisation de cookies pour réaliser des statistiques de visites","dismiss":"Accepter","learnMore":"Plus d'infos","link":"http://must-assurances.com/mentions-legales.php","theme":"light-bottom"};
</script>
<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/cookieconsent2/1.0.9/cookieconsent.min.js"></script>
<head>
    <meta charset="UTF-8">
    <title>MUST Assurances</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta http-equiv="x-ua-compatible" content="ie=edge">
    <meta name="description" content="Site internet de la SAS MUST"/>
    <meta name="keywords" content="assurance, nautique, courtier"/>
    <meta name="author" content="MUST Assurances"/>
    <link rel="apple-touch-icon" sizes="57x57" href="img/favicon/apple-touch-icon-57x57.png">
    <link rel="apple-touch-icon" sizes="60x60" href="img/favicon/apple-touch-icon-60x60.png">
    <link rel="apple-touch-icon" sizes="72x72" href="img/favicon/apple-touch-icon-72x72.png">
    <link rel="apple-touch-icon" sizes="76x76" href="img/favicon/apple-touch-icon-76x76.png">
    <link rel="apple-touch-icon" sizes="114x114" href="img/favicon/apple-touch-icon-114x114.png">
    <link rel="apple-touch-icon" sizes="120x120" href="img/favicon/apple-touch-icon-120x120.png">
    <link rel="apple-touch-icon" sizes="144x144" href="img/favicon/apple-touch-icon-144x144.png">
    <link rel="apple-touch-icon" sizes="152x152" href="img/favicon/apple-touch-icon-152x152.png">
    <link rel="apple-touch-icon" sizes="180x180" href="img/favicon/apple-touch-icon-180x180.png">
    <link rel="icon" type="image/png" href="img/favicon/favicon-32x32.png" sizes="32x32">
    <link rel="icon" type="image/png" href="img/favicon/android-chrome-192x192.png" sizes="192x192">
    <link rel="icon" type="image/png" href="img/favicon/favicon-96x96.png" sizes="96x96">
    <link rel="icon" type="image/png" href="img/favicon/favicon-16x16.png" sizes="16x16">
    <link rel="manifest" href="img/favicon/manifest.json">
    <link rel="shortcut icon" href="img/favicon/favicon.ico">
    <meta name="msapplication-TileImage" content="img/favicon/mstile-144x144.png">
    <meta name="msapplication-config" content="img/favicon/browserconfig.xml">
    <link rel="stylesheet" href="css/landio.css">
    <link rel="stylesheet" href="css/style.css">
    <link rel="stylesheet" href="css/animate.css">
    <link rel='stylesheet' type='text/css' href='https://fonts.googleapis.com/css?family=Merriweather:400,300,300italic,400italic,700,700italic,900,900italic%7CLato:400,100,100italic,300italic,400italic,300,700italic,900,900italic,700'>
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css">
</head>

  <body class="animated fadeIn"></body>

Do you have any ideas?

A:

The start tag for the <head> element is optional. A <script> element cannot be a child element of the <html> element.
Consequently, <script type="text/javascript"> implies the start of the <head> element so when you explicitly type <head> you are trying to open a <head> instead another <head> which is not allowed.
Either:

Move <head> to before the <script type="text/javascript"> or
Remove the explicit <head> start tag entirely.

