Mine is set to 1440, when I get “logged out” I just see a white screen, I’ll do some checks today but I’m not setting my own cookies only sessions to verify loggged_in in my app and those shouldn’t expire until browser closed.
How it works currently (using the PHP script).
User clicks login button - PHP script does its thing - you login at discourse - if that is successful - set the sessions.
Maybe there is a better way to do it, I’m not sure.
So you are using Discourse as SSO provider and you having issue in your php application. In that case there is nothing you can do from Discourse side. You have to check your PHP session configuration. Discourse part of the SSO is verifying the user login and sending the response only. Your application should handle the rest.