What i am doing wrong? header location dont work

i have a simple page with a puzzle where if you solve the password, you move to the next step,
my code does work in plain html files but does not on wordpress with your plugin, why?
when the password is correct isntead of load a new secret page, it fails, and loads itself with just the title

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<?php
$pass = $_POST[‘pass’];
if($pass == “test”){
header(“Location: next2121.php”);
}else{
if(isset($_POST)){
?>
<form method=”POST” action=””>
<input type=”password” name=”pass”></input>
<input type=”submit” name=”submit” value=”Continue”></input>
</form>

<?php
}
}
?>

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