I have been using Django for my application for quite some time now. I have had a problem that users get logged out suddenly.
Users enter information using an admin model to enter information in a text area(using Django MarkitUp), when they click save they are redirected to the login page.
My session expiry is set to 2 weeks(1209600) and the users have logged in the same day before entering information in the textarea.
Are you sure your redirect URL matches your sessions-related settings?