The LDAP portal configuration needs to be changed from Database to Network authentication.
To change the portal authentication:
Log in to http://localhost with a username that has Host Admin privileges and go to Admin.
In the Portals section click Portals.
Click the edit icon on next to the portal you want to configure to LDAP authentication. This open the portal configuration settings.
Change Database to Network on the drop down list.
Browse to the URL defined when you created the LDAP portal. You should be able to log in with a network username and password. The LDAP setting defined so far will allow any user for the domain to log into Skyline with their network username and password.