If immediately after logging in into HostBill admin area you're being logged out, it probably means that your server cannot keep session data properly.

It can be caused by various reasons, please check that:

• PHP can write to temp folder (usually /tmp) to store session data
• your /tmp partition is not running out of space
• if you're using Interworx with jails, the session.save_path configuration in php.ini needs to point to directory with write permissions ie: doing chmod -R 333 /session_save_path solves the problem.
• to be sure, try clearing browser cache or using different browser