We have a problem sending email to some addresses. For some time everything was fine, but now for some reason we recieve "mailbox unavailable" when an email is send to a few adresses. Most addresses give no error and email is sent correctly to them. Our situation: An exchange 2007 on an Win 2003 R2 in our domain. In the DMZ we have an Edge Transport server on a win 2003 R2. The addresses we cannot send email to, i have tested them with a telnet session. That works fine. I installed Roll-up 3, but no change. Does anyone have an idea what to do now??

Hi, This type of error is usually associated with sending the email where the receiving machine will not accept messages from the sending machine. You need to look at the settings on your Exchange server to verify that you have all IP addresses from your web server associated. Note that your internal email may be sent through an internal IP address while the external messages are using an external IP address. I hope you got my point. Regards. Shafaquat Ali.M.C.I.T.P Exchange 2007/2010, M.C.I.T.P Windows Server 2008, M.C.T.S OCS Server 2007 R2, Phone: +923008210320

Hi, Does it happens in Outlook only or also in OWA? If u still have not tried with OWA then test it and tell us the result. Are all users having problem sending to those email addresses or only some specific users cant send to them? Tell us about these problematic mailboxes, did u migrate them or recreate them etc.? Regards, Laeeq Qazi|Team Lead(Exchange + Sharepoint + BES + DynamicsCRM) www.HostingController.com

I don't know if I understand you correctly, but here is some info. All mail traffic within our domain, about 500 users, works fine. Mail to external addresses works for 98%. External mail is sent throug our Edge Transport server, who is in our DMZ. All our users are getting the same error. But when I sent a mail from gmail or hotmail or an other mailbox outsite our domain, the mail was send correct. The send connector on the Edge gives : smtp * 100

The result for OWA is the same. All users are experiencing the same errors. The problematic mailboxes who can not be reached are external boxes in other domains. Strangly, those mailboxes can be reached from gmail, hotmail or other external mailboxes.

We have a problem sending email to some addresses. For some time everything was fine, but now for some reason we recieve "mailbox unavailable" when an email is send to a few adresses. Most addresses give no error and email is sent correctly to them. Our situation: An exchange 2007 on an Win 2003 R2 in our domain. In the DMZ we have an Edge Transport server on a win 2003 R2. The addresses we cannot send email to, i have tested them with a telnet session. That works fine. I installed Roll-up 3, but no change. Does anyone have an idea what to do now?? Hi, I'd like to know if you can successfully use telent to send email to those unavailable mailbox. Please try to use following website to check if your server has been listed in the blacklist. http://www.mxtoolbox.com/blacklists.aspx Besides, please try to post the detail NDR information here, especially the generation Server of the NDR. Regards, Xiu

Using a telnet session, we can sent a mail. Our domain is NOT in the blacklist.

Hi, Please post the detail NDR information here for further troubleshootings. Regards, Xiu