Good day. I and any members on my site have problem with login. Via firefox all working, but in IE I try to login and it will say you are redirecting to your account - it normal, but after 1 second it turn me back and not log in. I can try it many times, its the same. But If I delete all cookies I can Login one time, than I press logout and than I can`t login again. Only in IE. Where can be problem please?

Instead of using cookies for your log in. I suggest using session cookies. Session cookies are stored on the server instead of the users computer. I'm pretty certain this will fix your problem too. As from what I see your problem lies with IE and it's privacy security or P3P.

And where I can Set it please?

You can look up sessions here. But they're really simple, as sessions are very similar to regular php variables. Changing to sessions will make your life easier.

PHP Code:

<?php session_start(); //this MUST always be the first line in the php script

$_SESSION['username'] = 'monkey'; 
$_SESSION['userid'] = $userid; //you can set these to strings or variables

//to get rid of a $_SESSION variable...
unset($_SESSION['username']);

//to get rid of all the session variables, and used to log out
session_destroy;

?>

Sessions are the way to go when it comes to maintaining information about a user over a short term. Unless you set it to expire a session usually remains valid until a user closes his browser. Cookies are useful retrieving information about a user long after they have logged out or there session has otherwise died.

Converting to sessions may solve your browser compatibility issue, but I suspect that there might be a problem with your code considering that IE (even IE6) supports cookies. For future reference posting your code helps us help you