Password Change

I’ve just set all users to change password at next logon. Users in the office have no problem. Remote users connecting using Terminal Server have no problem. However, remote users connecting using Outlook (just to check email) cannot change theirpassword. They keep getting the following message:
“Your Windows password cannot be changed. Please verify your information and try again.”

Can anyone help. How can I allow remote user to change their password when connecting using Outlook? Or are they not suppose to be able to do so?

Thanks.

Kit