Email bounce backs and delivery failures

Question

Over the past few months my client has started having trouble sending emails to a few domains (worked fine for multiple years).  The timing of these failures seems to match the new anti-spam software ISP are using.
Our internal exchange server shuttles pop3 mail to our local ISP via popcon (program).  Not sure is the information in the message headers is the issue, how to change it, or what to do next.
One feedback:
"I also dealt with a similar issue a few days where an Exchange 2013 server which had been happily running for over a year, with the exact same settings as
it used for 3 years previous on Exchange 2010 suddenly and mysteriously stopped sending to certain recipients but randomly, with the same error message as we see here. We suspected later that perhaps some mail servers on the internet were tightening things
up when it comes to dealing with Spam etc."  The issue was in the Exchange servers FQDN. (Fully Qualified Domain Name)
So far I have:
1) restarted the ‘Transport Service’
2) Updated send connector EHLO or HELO to bcbuildingtrades.org
Here is a message header from a failed email:
Diagnostic information for administrators:
Generating server: bcyt.local
[email protected]
#550 4.4.7 QUEUE.Expired; message expired ##
Original message headers:
Received: from FILESERVER.bcyt.local ([fe80::f44a:5231:60f1:4519]) by
FILESERVER.bcyt.local ([fe80::f44a:5231:60f1:4519%14]) with mapi id
14.01.0218.012; Tue, 2 Sep 2014 11:26:01 -0700
From: BC Building Trades <[email protected]>
To: BC Building Trades <[email protected]>, BC Building Trades
        <[email protected]>
Subject: RE: John MacTavish BCBCBTU Constitution Meeting: Wednesday,
September 3, 2014
Thread-Topic: John MacTavish BCBCBTU Constitution Meeting: Wednesday,
September 3, 2014
Thread-Index: Ac/DEBF+4GZ9fh2STdipo6AwiH8sMQDyotzw
Date: Tue, 2 Sep 2014 18:26:00 +0000
Message-ID: <[email protected]>
Accept-Language: en-US, en-CA
Content-Language: en-US
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
x-originating-ip: [fd7b:c71e:611b:0:69a3:67a5:2baf:593a]
Content-Type: multipart/alternative;
        boundary="_000_B050148A9707274AA84DC8B1B93386997920417BFILESERVERbcytl_"
MIME-Version: 1.0

Answer 1

Hi
Can you not ask your ISP to whitelist those domains you sending to? Also just verify that your domain is not listed at all, you can do so on MXToolbox.com
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