LDAP from outside domain

[glynnj]

I am trying to create a script to tell me when a particular users password is going to expire. This is a remote user and only connects to the domain for his email through Outlook. This user does not get prompted to change his password before it expires. I have got the script to work from within the domain but not from the external users connection. This is the LDAP string -

LDAP://Server/CN=The User,OU=USERS,DC=mydomain

The response I get is "the server is not operational". What am I missing?

Thanks and regards,
Joe