Can't login to admin panel

[arrusr1]

I can't login to admin panel, removing admin_check_login($error); from admin/includes/admin_init.php i can go directly to admin without login and it works

what could be the problem?

[arrusr1]

I have tested everything, conclusion is that its a session issue or cookies issue, i even disabled cloudflare to see if this is the problem
sometimes i can login, most times when i enter correct login info to admin it just spins and then page time out
i saw this thread
viewtopic.php?f=28&t=988
and i think there is a problem again on some special occasions