Rails Cookies in Mobile

I’m currently using Redmine and I have a client website using Ruby on Rails with Devise and both seem to suffer the same problem:

On iOS, both safari and Chrome, the cookie don’t seem to be kept after closing the browser window, but on desktop, I haven’t had to login for over half a year already.

Is there a special setting I need to set in Rails to remember the cookie? For my devise, I’ve already have rememberable set on my devise model.

Is there something special I need to do to make this work better on mobile?

Nothing special, just make sure you aren't using session cookies. Those go away when the browser is closed. What's the expiration of the session cookie? (hint, look in config/initializers/session_store.rb)

Mine looks like this:

Codebase::Application.config.session_store :active_record_store, :expire_after => 1.years