Exchange ser 2000 Front end and Backend?

I have installed Exchage 2k front and backend servers now i have problem i.e. when i promote my first exchage server to Front end and other made Backend , when i create a user on the OU or in Default users i get the erroe that new users E-mail address is not shown in the AD user manager and even not in Exch System Manager. Why is it happening, and receipient policy is properly configured.