I have an Exchange 2003 dev instance and also have some contacts with SMTP & X400 email addresses. I can successfully send emails using OWA to their SMTP mail addresses but when I try to specify the X400 email addresses, then it complains that the user is not present and asks me to correct the mail address. The various options of specifying the X400 mail address in OWA that I have tried are: c=US;a= ;p=First Organizati;o=Exchange;s=cdolast;g=cdofirst; /c=US/a= /p=First Organizati/o=Exchange/s=cdolast/g=cdofirst@testdomain.com x400:/c=US/a= /p=First Organizati/o=Exchange/s=cdolast/g=cdofirst@testdomain.com Could please guide me on how to use it? Any help would be appreciated. Thanks, Kamal Arora

put the x400 address is square brackets [x400:c=US;a= ;p=First Organizati;s=cdolast;g=cdofirst;]

Hey Jim, Thanks for your help. I tried your suggestion and OWA does allow to send the message when email-address is enclosed in square brackets. However, it's still not delivered and I get a notification as below: The following recipient(s) could not be reached: c=US;a= ;p=First Organizati;s=cdolast;g=cdofirst;on7/29/200910:01 AMThe message could not be delivered because the recipient's destination email system is unknown or invalid. Please check the address and try again, or contact your system administrator to verify connectivity to the email system of the recipient. So any thoughts on this? Thanks, Kamal

I also just noticed that at the end of NDR, I get an error code as below: <S-17125.testdomain.com #5.1.2> Googled this a bit and found: 5.x.xpermanent failure x.1.2bad destination system address

Hi,Did you create the X.400 connector in the Exchange server in order to communicate with X.400 email address?ThanksAllen