Hello, me again with another issue.... :), Exchange 2003 SP2, SBS 2003 Users are reporting that they have emailed a specific domain and the email is in Sent Items. Other party never receives it. No NDR is ever generated. I rebooted the server tonight for an unrelated patch and a batch of NDRs were delivered to various mailboxes relating to email sent some days or weeks ago. I have googled this and it appears to be a known issue, but would welcome some confirmation or explanation about what to do. Many thanks.