Web Mail User Session Expires
For security purposes, the Web Mail user session will expire (logout) after 2 hours of inactivity. When this occurs, any unsaved changes may be lost. Inactivity is considered to be staying on a single page for too long. If you are composing a message, we suggest saving a draft often, or compose the message off-line, in a text editor or similar.
Tip: If you are using Web Mail on a public computer, be sure to choose Logout, and exit/quit the web browser after you are done using Web Mail.