```ruby
# Be sure to restart your server when you modify this file.

CartoDB::Application.config.session_store :cookie_store, :key => '_cartodb_session', :domain => CartoDB.domain
```

Use root domain as session cookie domain
user
```ruby
# Be sure to restart your server when you modify this file.

CartoDB::Application.config.session_store :cookie_store, :key => '_cartodb_session', :domain => ".cartodb.com"
```
assistant