In Security Analytics there is a web timeout setting. If there is no activity in the browser, it will automatically log users off after X number of minutes (defined in Settings > Web Interface > Inactivity Timeout). The default setting is 5 minutes but can be increased to a maximum of 1 week. If running a report that takes longer than the web timeout, the browser may time out before the report completes. Once logged off, the report will automatically terminate within 5 minutes.
Security Analytics 8.3.1
All web browsers
The configured Web Interface Inactivity Timeout is shorter than the time required for the report to generate.
There are a few ways to improve chances of not getting logged off prematurely.
If users get logged out before the report finishes, log back in and rerun the report from scratch.