Unable to Limit the Users via Additional User DN

Following the instructions via this link;
https://confluence.atlassian.com/display/CONFKB/How+to+Change+the+Number+of+Users+Synchronized+from+LDAP+to+Confluence

Tried using "Additional user DN" for Email alias confluence-users, but only get errors when applying that.

I've attached screen shots of the configuration and the results.

I need this resolved immediately as I can't update Confluence.