cosa ho sbagliato in questo script di redirect?

[MR.GIO93]

salve, ho creato questo script di redirect in base alla lingua del browser ma mi da un errore, cosa ho sbagliato ???

<?php
function redirect() {
    
    $lang=substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);

    switch($lang) {
        case "it": {
            header("Location: redirect/index.html");
            break;
        }
        case "en": {
            header("Location: redirect/code-24/index.html");
            break;
        }
        case "fr": {
            header("Location: redirect/code-23/index.html");
            break;
        }
        case "de": {
            header("Location: redirect/code-22/index.html");
            break;
        }
        case "es": {
            header("Location: redirect/code-21/index.html");
            break;
        }
        case "ru": {
            header("Location: redirect/code-20/index.html");
            break;
        }
        case "ja": {
            header("Location: redirect/code-19/index.html");
            break;
        }
        case "pt": {
            header("Location: redirect/code-18/index.html");
            break;
        }
        case "fi": {
            header("Location: redirect/code-17/index.html");
            break;
        }
        case "ar": {
            header("Location: redirect/code-16/index.html");
            break;
        }
        case "cs": {
            header("Location: redirect/code-15/index.html");
            break;
        }
        case "da": {
            header("Location: redirect/code-14/index.html");
            break;
        }        
        case "no": {
            header("Location: redirect/code-13/index.html");
            break;
        }        
        case "sv": {
            header("Location: redirect/code-12/index.html");
            break;    
        }        
        case "tr": {
            header("Location: redirect/code-11/index.html");
            break;
        }        
        case "zh": {
            header("Location: redirect/code-10/index.html");
            break;
        }        
        case "zh": {
            header("Location: redirect/code-9/index.html");
            break;
        }        
        case "el": {
            header("Location: greco.php");
            break;
        }        
        case "ga": {
            header("Location: redirect/code-8/index.html");
            break;
        }        
        case "nl": {
            header("Location: redirect/code-7/index.html");
            break;
        }        
        case "uk": {
            header("Location: redirect/code-6/index.html");
            break;
        }        
        case "th": {
            header("Location: redirect/code-5/index.html");
            break;
        }        
        case "pl": {
            header("Location: redirect/code-4/index.html");
            break;
        }        
        case "ro": {
            header("Location: redirect/code-3/index.html");
            break;
                    
        default: {
            header("Location: redirect/code-24/index.html");
        }
    }

}
redirect(); 
?>

grazie in anticipo