I would start with EXCH event logs and SMTP logs. Probably won't hurt to crank up the latter too temporarily. Also try running SMTPdiag tests to those users' recipients, if they're not internal.
Alex -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tony Nguyen Sent: Wednesday, October 11, 2006 12:44 AM To: Exchange Discussions Subject: Unknown User I need some help with this please. I have been report from some of my users say that when they do a reply to an email it get returned with SMTP; 550 5.1.1 User unknown and some time the reply work fine. Where should I start trouble shooting this. I never had this problem before until a couple of days ago. Nothing was change in the system too. Thank Tony [Disclaimer] The receiving party represents and warrants that no technical data furnished by the disclosing party shall be exported from the United States without first complying with all requirements of the International Traffic in Arms Regulations and the Export Administration Act and regulations hereunder, including the requirement for obtaining any export license, if applicable. The receiving party shall first obtain the written consent of the disclosing party prior to submitting any request for authority to export any such technical data. The receiving party shall indemnify and hold the disclosing party harmless of all claims, demands, damages, costs, fines, penalties, attorney's fees and all other expenses arising from failure of the Receiving party to comply with this clause or the International Traffic in Arms Regulations and the Export Administration Act and applicable regulations. The receiving party may make the technical data furnished available only to its employees, contract employees and other parties working on the program within the receiving party's facility and having a "need to know" with respect to said purpose. In connection therewith, the parties shall advise each such employee, contract employee or other party of its obligations under this agreement. _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Web Interface: http://intm-dl.sparklist.com/read/?forum=exchange To subscribe: http://e-newsletters.internet.com/discussionlists.html/ To unsubscribe send a blank email to [EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with. _________________________________________________________________ List posting FAQ: http://www.swinc.com/resource/exch_faq.htm Web Interface: http://intm-dl.sparklist.com/read/?forum=exchange To subscribe: http://e-newsletters.internet.com/discussionlists.html/ To unsubscribe send a blank email to [EMAIL PROTECTED] Exchange List admin: [EMAIL PROTECTED] To unsubscribe via postal mail, please contact us at: Jupitermedia Corp. Attn: Discussion List Management 475 Park Avenue South New York, NY 10016 Please include the email address which you have been contacted with.
