Recipient failure and rfc822

Question

Several emails not going through today, here's raw source of mail...what's it mean(user unknown in local recipient list)? (I added "xxx" in emails to hide addresses)
Received: from alnrmhc14.comcast.net (localhost[127.0.0.1])
by comcast.net (alnrmhc14) with ESMTP
id <20070922005220b1400nslkhe>; Sat, 22 Sep 2007 00:52:20 +0000
From: Mail Delivery Subsystem <[email protected]>
Subject: Returned mail: delivery problems encountered
Message-Id: <[email protected]>
Date: 22 Sep 2007 0:52:19 +0000
To: <[email protected]>
Mime-Version: 1.0
Content-Type: multipart/report; report-type=delivery-status; boundary="46f46743.4019.6+comcast.net="
--46f46743.4019.6+comcast.net=
Content-Type: text/plain
A message (from <[email protected]>) was received at 21 Sep 2007 23:53:00 +0000.
The following addresses had delivery problems:
<[email protected]>
Permanent Failure: 550<[email protected]>:_Recipient_address_rejected:_User_unknown_in_local_recipienttable
Delivery last attempted at Sat, 22 Sep 2007 00:46:09 -0000
--46f46743.4019.6+comcast.net=
Content-Type: message/delivery-status
Reporting-MTA: dns; comcast.net
Arrival-Date: 21 Sep 2007 23:53:00 +0000
Final-Recipient: rfc822; <[email protected]>
Action: failed
Status: 5.0.0 550<[email protected]>:_Recipient_address_rejected:_User_unknown_in_local_recipienttable
Diagnostic-Code: smtp; Permanent Failure: Other undefined Status
Last-Attempt-Date: Sat, 22 Sep 2007 00:46:09 -0000
--46f46743.4019.6+comcast.net=
Content-Type: message/rfc822
Received: from [98.203.159.250] (c-98-203-159-250.hsd1.wa.comcast.net[98.203.159.250])
by comcast.net (alnrmhc14) with SMTP
id <20070921235257b1400ooapse>; Fri, 21 Sep 2007 23:53:00 +0000
Mime-Version: 1.0 (Apple Message framework v752.2)
Message-Id: <[email protected]>
Content-Type: multipart/alternative; boundary=Apple-Mail-5--489303981
To: <[email protected]>
Subject: VERY GOOD TAPE RENTAL!
From: <[email protected]>
Date: Fri, 21 Sep 2007 16:52:57 -0700
X-Mailer: Apple Mail (2.752.2)
--Apple-Mail-5--489303981
Content-Transfer-Encoding: 7bit
Content-Type: text/plain;
charset=US-ASCII;
delsp=yes;
format=flowed

Answer 1

This is a message from the mail delivery agent at webtv.com: It doesn't know who [email protected] is. The exact text of the message is up to the mail delivery agent, but basically what it's saying is that it received a request for local delivery (i.e., to a user actually on the system, as opposed to something that's being sent out to another system) for [email protected], but it couldn't find that user.
The cause could be anything from a typo in the recipient address to a problem in the configuration at webtv.com - or even at comcast.net, though that's less likely. Or it could be that xxx has moved this account away from webtv.com!
-- Jerry