After changing your active directory user password Outlook 2013 keeps prompting for password. Doesn’t matter if you enable remember my credentials option.
You need to delete your saved credentials in Credential Manager.
Open Credential Manager in Control Panel. Click on Windows Credentials. Under Generic Credentials you should have MS.Outlook.15:firstname.lastname@example.org. Delete MS.Outlook.15:email@example.com.
Open Outlook. Use your active directory user account and enable remember my credentials option.
For more information: http://support.microsoft.com/kb/2762344