I have been getting the "error" in the subject lately. It only happens on some emails and generally to only some recipient domains (gmail being one) but not even all the time for them. The emails do always get delivered but are delayed for several hours at least each time. It's becoming an issue as it is fairly often now, and I would like to find a solution. Since it's happening to recipients other than just gmail, and as far as I can tell sending from my domain is the only one having this issue, there must be something wrong internally.
Delayed bounce message:
Diagnostic information for administrators:
Generating server: MyMachine.MyDomain.local
somebody@gmail.com Remote Server returned '400 4.4.7 Message delayed'
Original message headers:
Received: fromMyMachine.MyDomain.local (192.168.1.3) by MyMachine.MyDomain.local (192.168.1.3) with Microsoft SMTP Server (TLS) id 15.0.712.24; Tue, 3 Dec 2013 12:34:48 -0500 Received: fromMyMachine.MyDomain.local ([::1]) byMyMachine.MyDomain.local ([::1]) with mapi id 15.00.0712.012; Tue, 3 Dec 2013 12:34:36 -0500 From: Me <me@MyExternalDomain.com> To: " Somebody <somebody@gmail.com> Subject: start Thread-Topic: start Thread-Index: Ac7wTe7MQ15PInWfSkyzZYwfpa+47Q== Date: Tue, 3 Dec 2013 17:34:35 +0000 Message-ID: <f67e412e61524289af789970d3a3ff22@MyMachine.MyDomain.local> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: yes X-MS-TNEF-Correlator: x-originating-ip: [192.168.1.52] Content-Type: multipart/related; boundary="_004_f67e412e61524289af789970d3a3ff22MyMachineMyDomainlocal_"; type="multipart/alternative" MIME-Version: 1.0
When the message is in the Exchange Queue, it says:
"451 4.4.0 DNS query failed. The error was: DNS query failed with error ErrorTimeout"
I ran SMTPDiag and everything passed. I can copy/paste the results if needed.
Other info that may be helpful:
Email server domain: mail.MyExternalDomain.com
Mail is SENT from: IPaddress1
Mail is accessed remotely (OWA/outlook/active sync) via: IPaddress2 (2 ip addresses here to easily route through firewall)
The mx record points to our spam filter's domain name, our offsite spam protection, so that naturally doesn’t match ours.
The Exchange send connector is set to have a FQDN of mail.MyExternalDomain.com for responses to HELO/EHLO
I had our ISP set IPaddress1 to have an rdns of mail.MyExternalDomain.com
I'm unsure that the recipient's server is the one even delaying it so the DNS info may not be a factor. It seems to me to be something internal but I can't figure out what that may be.
Thank you for any suggestions!