Acquia recommends customers with sites using Acquia Cloud Edge CDN prior to 1 June 2016 make a configuration change to improve their Drupal administrator experience.
Currently, Drupal administrator user sessions do not remain logged in for sites using Acquia Cloud Edge CDN. Additionally, page content for those user sessions may be served from the Cloud Edge cache, even though a Page Rule has been added with the Bypass Cache Cookie value set to:
This rule is intended to force users with any of these session cookies to bypass the Edge CDN cache entirely, ensuring they see the most up-to-date page content. However, this setting is not maintaining the admin user’s session on Drupal.
For an improved admin experience, the Bypass Cache Cookie value should be set to:
Note the addition of SSESS.* as well as periods after SESS and after LOGIN_.
This will allow you to maintain a persistent login.
Customers with sites implementing Acquia Cloud Edge CDN after 1 June 2016 already have this setting implemented by default.
If you have any questions, you can contact Acquia Support by creating a ticket at https://insight.acquia.com/support or visiting the Help Center.