PERM_FAILURE: SMTP Error (state 16): 550 5.7.1

[timbo343]

I get a few messages that bounce back from a couple of staff that send things from outside to inside.

Below is the error:

---------- Forwarded message ----------
From: Mail Delivery Subsystem <mailer-daemon@googlemail.com> 
Date: 15-Jul-2007 10:50
Subject: Delivery Status Notification (Failure)
To: xxxxxx@xxxxx.com

This is is an automatically generated Delivery Status Notification 

Delivery to the following recipient failed permanently:

    xxxxxx@xxxxxx.co.uk

Technical details of permanent failure:
PERM_FAILURE: SMTP Error (state 16): 550 5.7.1 Requested action not taken: message refused

  ----- Original message -----

Received: by 10.90.113.20 with SMTP id l20mr2504227agc.1184493035994;
       Sun, 15 Jul 2007 02:50:35 -0700 (PDT) 
Received: by 10.90.91.2 with HTTP; Sun, 15 Jul 2007 02:50:35 -0700 (PDT)
Message-ID: <309932ac0707150250q25a6b7b0pa34ddc51d4f736f1@mail.gmail.com >
Date: Sun, 15 Jul 2007 10:50:35 +0100
From: xxxxxxxxx
Reply-To: xxxxxxx
To: xxxxxxxx
Subject: Scratch
MIME-Version: 1.0
Content-Type: multipart/alternative;
       boundary="----=_Part_34712_22026813.1184493035935"

------=_Part_34712_22026813.1184493035935
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Content-Disposition: inline 

http://scratch.mit.edu/

------=_Part_34712_22026813.1184493035935
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

  ----- Message truncated -----

Has anyone seen this message before or know what the solution is?

If so please let me know

Thanks

[Geoff]

The mail server doesn't like you, either because:

1) You need to authenticate.
2) Your blacklisted.
3) The recipients mailbox is broken
4) The recipient has some sort restriction on who can send mail to them.