sharepoint inbox automatic login

In order to login the MyInbox automatically, please configure the Outlook web access(OWA) to use Windows Integrated authentication, and make sure we can use the Internet Explorer(IE) to access the mail box without login.
If you are promptting login dialog, it might be caused by the IE cannot use the current credential to access the mail box. Please follow these steps to fix it:

1. Open IE
2. Click the menu Tools > Internet Options...
3. Go to "Security" tab
4. Select "Intranet sites" or "rusted sites" zone
5. Add the OWA to the zone.
6. Click OK to apply.
7. Click "Custom Level"
8. Check the item "Auto logon with current username andd password"
9. Click "OK" to apply.

Now, you should be able to access the OWA without login, and then you are able to access the MyInbox directly within a SharePoint site.