Posted on 2010-11-23
I have a user that sent an email and got the following response:
An error occurred while trying to deliver this message to the recipient's e-mail address. Microsoft Exchange will not try to redeliver this message for you. Please try resending this message, or provide the following diagnostic text to your system administrator.
#< #5.0.0 X-Postfix; host smtp801.microsoftonline.com[xxxxxxxxxx] said: 550 5.1.1 User unknown (in reply to RCPT TO command)> #SMTP#
Assuming the email address is valid, what is the problem, and what setting do I change from exchange 2007 management console?