header(location) does not work?

if you say this, one of the possible problem is as follows: Your wrong code may be : header(" refresh: 2;url=sign_in.php "); You may be correct it by deleting the first backpace between " " such as the following code: header("refresh: 2;url=sign_in.php "); Believe or not this foolish whitespace causes the problem .It is funny,isnt it? Or if you are still problem with error.Delete echo s before headers. I don't understand why but it works sometimes but doesnt work sometimes.