How do I preserve user sessions across subdomains? I have defaultCookieDomain set to .site.com
I am logged into www.site.com
I expected to also be logged into sub.site.com (which is pointing to the same web root), but I'm not.


What am I missing?
Figured this out, the appId setting was the culprit: https://craftcms.com/docs/config-settings#appId

If using this setting, you probably don't want to set it to something dynamic (as I was, e.g. md5($url)).