In 2.2.2, I tried changing the session_cookie_domain setting to have ".domain.co" for its value, in order to share session data across sub domains.
After setting this, clearing the cache, flushing perms and logging everyone out, I couldn't log back into the manager (i also tried manually clearing the cache folder).
Changing the setting back to blank cures the problem and you can login again...
Anyone knows why?
Once you have changed the session_cookie_domain settings you need to remove your session cookies in your browser for the site in order to login again.
