Hi, We add before ABC.net SMTP domain in our Exchange Organization but today we remove it by using Internet Mail Wizard and remove from DNS but still the users in organization can receive email but they report that can not send email to ABC.net I have one message in DNS Events that said: Event Type: Warning Event Source: DNS Event Category: None Event ID: 4521 Date: 4/25/2011 Time: 1:48:44 PM User: N/A Computer: mycompanyDC1 Description: The DNS server encountered error 32 attempting to load zone ABC.net from Active Directory. The DNS server will attempt to load this zone again on the next timeout cycle. This can be caused by high Active Directory load and may be a transient condition. For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp. I found there record ABC.net still in DNS but i delete also, I restart the DC server and try to send email to ABC.net but failed. In my company try to Telnet ABC.net and failed but if i telnet ABC.net from any where it work. How can fix this issue?