We are having a similar issue as described above, and we are using OCS version 2.3.5 installed here: http://naasn2014.org
... Logging in creates an infinite loop back to the login page. It seems intermittent, occasionally, it will work, usually, it does not. (Perhaps a difference in whether one logs in from the sidebar block or the main login? Usually, difficult to replicate... can be some hours or days later and still loop at login.) It seems to be happening to all accounts, whether users or conference managers. I have set 'session_check_ip = Off' in the config.inc.php ... Would it help to see a scrubbed version of the whole config? What sort of info could I give you to help clarify what is causing this problem and help me to fix it as soon as possible? Is it happening because I didn't click "logout" on a previous session? Is there a workaround solution to this?