some external emails can't be received from gmail&yahoo,

Dear experts ,

now days we faced problem in our mail server .the problem is we can send emails to gmail&yahoo,but we can't receive from them ,another thing which very strange if we forward emails from yahoo or gmail to any Recipients in our domain  he will  receive these emails.please see delivery notification from gmail&yahoo

NOTE:WE USE MSEXCHANGE 2003

GMAIL.

Mail Delivery Subsystem <mailer-daemon@googlemail.com>        to me
      show details       9:35 pm (19 minutes ago)
This is an automatically generated Delivery Status Notification

Delivery to the following recipient failed permanently:

   xxxxx@xxxxx.com

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 10.66.220.17 with SMTP id s17mr1572218ugg.1185996934849;
       Wed, 01 Aug 2007 12:35:34 -0700 (PDT)
Received: by 10.66.240.18 with HTTP; Wed, 1 Aug 2007 12:35:32 -0700 (PDT)
Message-ID: <57c50bb90708011235m717ae983nc13c8f40da4c0cb4@mail.gmail.com>
Date: Wed, 1 Aug 2007 21:35:34 +0200
From: "ahmed ramadan" <xxxxxxx@gmail.com>
To:  xxxxx@xxxxx.com
Subject: r
MIME-Version: 1.0
Content-Type: multipart/alternative;
       boundary="----=_Part_66762_3169685.1185996934804"

------=_Part_66762_3169685.1185996934804
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

test

------=_Part_66762_3169685.1185996934804
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit

  ----- Message truncated -----


YAHOO.

Hi. This is the qmail-send program at yahoo.com.
I'm afraid I wasn't able to deliver your message to the following
 addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<xxxxx@xxxxxx.com>:
62.230.64.227 failed after I sent the message.
Remote host said: 550 5.7.1 Requested action not taken: message refused

--- Below this line is a copy of the message.

Return-Path: <xxxxxxa@yahoo.com>
Received: (qmail 269 invoked by uid 60001); 1 Aug 2007 14:31:50 -0000
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws;
  s=s1024; d=yahoo.com;

  h=X-YMail-OSG:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-ID;

  b=qe3LrzqI1MNzSuEi6DQiNZ1I2XnvXslxKwyl5ZcntBgLmgbZuw1AEckONGyWI4klotVIXgI8F+jzDrV+y8eAO5ZxbXrX8a3uovRuDokNC0VzqYuacoO7Xd2zxc2i5zqd/alGnUJm8NS0nZ8mFOVnvQw/PlefPSQfIymQamJOYXA=;
X-YMail-OSG:
 JgPN3TMVM1kg7CgcUB6nH3sQPIb.xvN.Rn6S4rYlLpyspCmp8sMvbkAUVU.MbDsWQg--
Received: from [62.240.63.233] by web30512.mail.mud.yahoo.com via HTTP;
 Wed, 01 Aug 2007 07:31:50 PDT
Date: Wed, 1 Aug 2007 07:31:50 -0700 (PDT)
From: xxxxxxa < xxxxxxa@yahoo.com >
Subject: testttttttttttttttttttttttttttttttttttttttt
To: xxxxx@xxxxxx.com
MIME-Version: 1.0
Content-Type: multipart/alternative;
 boundary="0-401367852-1185978710=:87482"
Content-Transfer-Encoding: 8bit
Message-ID: <180155.87482.qm@web30512.mail.mud.yahoo.com>

--0-401367852-1185978710=:87482
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
Recipient


your help please AS.AB