Why does session don't work in rails

I am using rails 2.3.9 on development environment. On production session work perfectly, but on development everything that uses session doesn't persit. For example login and local开发者_如何学Goe functionalities do not work.

I use session[:locale] and update cookies[:locale] as well,all executing without any errors, but after going to another page, it uses the old locales. What might be a cause of this?