Hello everyone I would appreciate any help or comment to get help on this issue. We have a user that is sending invitation based on calendar to internal users. But after users receive the invitation and accept it sending the reply back, they get none deliverable message to a different email address which was gone and deleted 6 months ago from company. Why is this happening and where can I track it down? We don't accept that mail address and the whole user and mail box are deleted. Exchange 2003 sp1 on windows 2003 standard sending outlook 2003 on xp sp2 Attention: This message, including any attachment(s), is intended only for the use of the individual(s) to which it is addressed and may contain information that is privileged or confidential. Any other distribution, copying or disclosure is strictly prohibited. If you are not the intended recipient or have received this message in error, please notify us immediately by reply e-mail and permanently delete this message including any attachment(s), without reading it or making a copy. Any outgoing message has been scanned for possible harmful file(s) or script(s), but it is your sole responsibility to run detection tools as we won't guarantee the safety of message(s).