Zapomenuté heslo skript PHP databáze mysqli

Mám chybu v resetpass.php

Nejprve musíte použít $_GET['code'] získat aktivační kód a uložit jej do skrytého pole

zde je upravený kód, který by měl fungovat.

<?php

if(isset($_POST['pass'])){
$pass = $_POST['pass'];
$acode=$_POST['code'];

$con=mysqli_connect("xxx","xxx","xxx","xxx");
// Check connection
if (mysqli_connect_errno())
{
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$query = mysqli_query($con,"select * from login where activation_code='$acode'")
or die(mysqli_error($con)); 

if (mysqli_num_rows ($query)==1) 
{
$query3 = mysqli_query($con,"update login set Password='$pass' where activation_code='$acode'")
or die(mysqli_error($con)); 

echo 'Password Changed';
}
else
{
echo 'Wrong CODE';
}
}
?>

<form action="resetpass.php" method="POST">
<p>New Password:</p><input type="password" name="pass" />
<input type="submit"  name="submit" value="Signup!" />
<input type="hidden" name="code" value="<?php echo $_GET['code'];?>" />
</form>