MAPI and MS Exchange Server

Has anyone made an application in Delphi for Microsoft Exchange Server?
I do it now! BUT I have a problem. I get the mail
return with following message:

From: System Administrator
Sent: 4. november 1996 17:16
Subject: Undeliverable: EX:Voice2

Your message did not reach some or all of the intended recipients.

Subject: test
Sent: 04-11-96 17:16:32

The following recipient(s) could not be reached:

'EX:Voice2' on 04-11-96 17:16:32
The message was undelivered because the specified recipient postal
address was incorrect

What is wrong?
What must the address be?


Thomas Boege