LOGIN SESSION EXPIRED
Once you have logged on to your mailbox using the Web Mail Client, a timer is invoked. This timer keeps track of the duration of your mail session. If the web mail client is idle for more than the specified log-out time (the default is 30 minutes), it will automatically log you out displaying the message:

To refresh your user credentials, re-log in the authentication window on the Web Mail Client.

To change the Web Mail Client's default log-out time, consult your system administrator.