ether/etherpad-lite — pull request #2410 by Gared (2014-12-28 17:49:08+00:00)
Title: Notify user if cookies can't be created

It's related to #2408
To reject cookies from being created in firefox you can install firebug. Go to the cookie tab and change the dropdown from "Default (Accept cookies)" to "Deny cookies from...".
Or you can simple reject all cookies in all browser settings from being created.
After that, try to open a pad url.