If you are logged in via SSO the default log-out period after inactivity is 2 hours. If you are logged in via email and password, the log-out period is 24 hours.
You can adjust the SSO timeout length via School Settings.
1. Click your name in the upper-right corner of the screen, then click School Settings.
2. From the menu on the left, click SSO Preferences.
3. Scroll to the field User timeout, then enter the preferred number of hours. Click Update SSO Preferences, in the lower-right corner of the screen, to save your changes.