The last day or two there has started to be an issue where a user logs in, tries to view a report, and then is immediately logged out. I myself experienced this, but slightly different. I logged on, navigated to web statistics > audit log, but when the log was loading I was kicked out. I'm not sure what could be the issue. To resolve I've had to stop and restart the Web Viewer.
Release : 12.1
When a user is kicked out to the 'An error has occurred...' and there is not information in the
expected logs