We installed an Small business server in an office with about 6 people. Originally they were not using the exchange server but were poping into their isp pop accounts (sonic.net)and downloading them into outlook exchange mailboxes.Months later we then got rid of their pop accounts from the isp, changed the mx record to have theirmail godirectlyinto the exchange server. Since the change we have added a couple of users to the company and the SBS server. The problem I am having is that anytime someone e-mails to a mailbox that is at sonic.net who was a part of the original server install get's ndr's send back and the mail does not work. However, you can e-mail the same e-mail addresses from the users who were added later and it will go through. I have worked with the isp (sonic.net) and they do not see the mail even reach their server when they are sent from the original users but when I send to the same address from the users who were added month's later they go through. I have looked in the message tracking center in the exchange system manager and it shows the following events when sent from the orignial users: smtp: Store Driver: Message Submitted from Store smpt: Message Submitted to Advanced Queuing smpt: Started Message Submission to Advanced Queue smtp: Message Submitted to Categorizer smtp: Message Categorized and Queued for Routing smpt: Message Routed and Queued for Remote Delivery smpt: Started Outbound Transfer of Message smpt: Non-Delivered Report (NDR) Generated When I send out mail from users added later is show it being actually delivered to the isp. Anyway any thought on what may be causing this would be a real help. Thanks.

Hi, What does the ndr say? Leif