automatic logout

[Deleted user]

The way JIRA is setup here the users are created in Crowd and then you can use this login for any tool (JIRA, Confluence, etc).
I'm also connecting through a VPN.

In this situation.... sometimes JIRA will logout automatically at random times.
For example I stopped using it 1 min ago and it logged out.

Sometimes I will leave it for 10 minutes without using and it won't logout.
But other times it logs out after very little time.

What could be causing this?

I checked the settings in the web.xml and they look fine.