My network administrator is on vacation and I don't have a clue what is going on here. If someone could tell me what to do, I would really appreciate it. We're running Exchange 2000 on a Win2K server with Norton antivirus on the Exchange server, our file and printservers and on our workstations. We have a Cisco Pix firewall. The Administrator's mailbox is filling up with undeliverables from "the System Administrator." Are we a Sobig victim? The undeliverables all have random subject lines and are addressed to random people. Here's one of the undeliverables: Your message did not reach some or all of the intended recipients. Subject: beebe Sent: 8/27/03 12:08 PM The following recipient(s) could not be reached: rejoice@xxxxxxxx on 8/27/03 1:21 PM There was a SMTP communication problem with the recipient's email server. Please contact your system administrator. <pewclimate.org #5.5.0 smtp;550 <rejoice@xxxxxxxx>: inactive user> What does this mean? Thanks. Jan MtPleasant