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

I have Microsoft Outlook 2007.

I am receiving all emails, and sometimes, even able to send them without the error message:

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

Subject: test
Sent: 11/22/2011 8:51 AM

The following recipient(s) cannot be reached:

'xxxx@xxxx.com' on 11/22/2011 8:51 AM
550 5.2.0 0EqJ1i00H2uf0uo01EqJfg 5.7.1 Unable to relay E9210


What is most confusing to me (other than the fact that I can sometimes reply to emails and send new ones) is the fact that sometimes when I send an email and receive this message, it actually does send the email.


Any insight? Thank you in advance!

melissakoehler said:

I have Microsoft Outlook 2007.
...Unable to relay E9210...

The last post in a long thread says:
"As you’ll see by the marked “answers”, the issue of “unable to relay for” is most often caused by misconfigurations in Exchange or Outlook authentication."
550 5.7.1 Unable to relay for