Every end user has an associated user session that takes up some of the Application Container’s memory. Therefore, the amount of memory available to your Application Container affects the maximum number of concurrent end users it can handle.
You can maximise the number of concurrent end users by tuning the Session Timeout on the Settings page of the Cloud Portal so it is right for your application.
The shorter the timeout the more quickly an end user’s session information is reclaimed and so the quicker new end users can be accommodated.
The default timeout of 30 minutes represents a good balance of maximising end users while providing the best experience for each one. Every application is different however and a longer or shorter timeout may be more effective for your application.