ok, after i did something then some people including me couldn't login
So I've done something else ... are you having the same problem again now?
Another possible problem is that you have the cookie security settings set to disallow cookies. You could try changing them to allow cookies completely or just from here. But you seem to have cookies so that might
not be it.
With the AOL thing, this is what I get from the phpbb help site -
"My AOL based users keep getting logged out!
phpBB2 uses sessions to keep track of users as they browse the board. These sessions use a combination of a unique session id and the users IP to identify each user. We make use of the IP as an extra safe-guard to help prevent sessions being hijacked (by discovering the unique session id).
Unfortunately this only works when the users IP is constant as they browse the board. For most users this will be the case. However certain providers route their users via a cluster of proxys. In some cases, particularly AOL this results in different IPs being forwarded as the user moves between pages. We take account of this by not checking the entire IP but only the first "three quads". Again in most cases this will be fine. However again AOL uses IPs which can vary so much that checking only the first two quads results in a fairly static IP being available for session validation."