Help with login!

I am using the php-login script. Everything has been working fine but suddenly now when I try logging in with an account (called user1) that has always worked previously, it simply redirects me to the login page. It does not error, it just redirects. Although if I try another account (user 2), I login normally but this one account (user 1) just does not seem to not want to login and just keeps redirecting me back when I try logging in.

Also, the script only works if I have the “Remember Me” box checked. I have a feeling that it is an issue with cookies, I have taken a code snippet here:

session_regenerate_id (true); //prevent against session fixation attacks.
// this sets variables in the session
$_SESSION['user_id']= $id;
$_SESSION['user_name'] = $full_name;
$_SESSION['user_level'] = $user_level;

//update the timestamp and key for cookie
$stamp = time();
$ckey = GenKey();
mysql_query("update users set `ctime`='$stamp', `ckey` = '$ckey' where id='$id'") or die(mysql_error());

//set a cookie

         setcookie("user_id", $_SESSION['user_id'], time()+60*60*24*365, "/");
         setcookie("user_key", sha1($ckey), time()+60*60*24*365, "/");
         setcookie("user_name",$_SESSION['user_name'], time()+60*60*24*365, "/");
header("Location: myaccount.php");

Although, it may be other things. For further reference, the script I am using is from here:


Was any changes made to the configuration of the server around the time the script stopped working properly?