a couple of things:
- You need to set "Member attribute uses DN" to 'Yes' if you are using MS Active Directory. Otherwise Moodle won't be able to match your users with the group members, and they won't get enrolled.
- Also, if you are using nested groups for your enrolments (you seem to be, as you have "Nested groups" set to yes), you have to specify the "Member of attribute" setting. This is 'memberOf' for MS Active Directory.
Hope that helps.