When setting up your environment for Single Sign-On across your other web applications (e.g., SharePoint) there are a few local machine settings that needs to be setup on the client side.
Inside the Intranet
1. Open Internet Explorer (IE) and go to Internet options.
2. Go to the Security tab, select Local intranet, and then click Sites.
3. Select Advanced ):
4. Enter your trusted URL domain(s) and select Add.
5. Select Custom level...
6. Under User Authentication, select Automatic logon only in Intranet zone.
Once configuration is complete, users will gain automatic access after logging in once to any of the Applications.
Outside the Intranet
1. Go to Control Panel > User Accounts > Credential Manager.
2. Select Add a Windows credential.
3. Enter in the URL address and Username/Password, then click OK.