Use the light version of Outlook Web App
The light version of Outlook Web App includes fewer features. Use it if you're on a slow connection or using a computer with unusually strict browser security settings. We also support the full Outlook Web App experience on some browsers on Windows, Mac, and Linux computers. To check out all the supported browsers and operating systems,
To protect against unauthorized access, your Outlook Web App session will automatically time out after a period of inactivity. If your session ends, refresh your browser and sign in again.