System is running Windows Server 2003/SP-2 & Exchange 2003. Clients are running Winsows XP/SP-2 and Outlook2003. When certain users are selected from the Global Address List and a message is sent, the following error message is returned: 'Username' 'Date' 'Time' The e-mail account does not existat the organization this message was sent to. Check the e-mail address, or contact the recipient directly to find out the correct address. If e-mail is sent from the person whose GAL entry did not work to the original sender, the problem disappears until Outlook is restarted. Any Ideas? Thanks.