Sending email issues via Outlook Client

SBSIAdmin used Ask the Experts™
As of yesterday we had one user complaining that they were getting email kickbacks when sending or replying to a specific domain. Today, I have at least 2-3 more that have issue with the same domain and now others.

IF we send or reply to an email using OWA (instead of the locally installed client), the emails go thru to the recepient.

I have tried deleting the NK2 file, but that didn't resolve the issue.

Some Outlook client installs can email to this domain, but some can't, unless they logon to OWA.

The kickback (NDR) is pasted below.

Any advice is greatly appreciated.

Thanks Amy
Your message did not reach some or all of the intended recipients.

      Subject:      testing emails from SBSI
      Sent:      01/05/2012 11:40 AM

The following recipient(s) cannot be reached:

      '' on 01/05/2012 11:40 AM
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <server.mydomain.COM #5.5.0 smtp;554 Denied [] (Mode: normal)>
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I would start diagnosing with going to and taking SMTP and blacklist test for your server.
I admit that is a little bit strange that remote server accepts mails form OWA.


Well, I ran thru the tool on all records found from our domain, the only finding was a warning
     Warning - Reverse DNS does not match SMTP Banner
The blacklist test didn't find anything either.

I agree that OWA shouldn't work either. I keep thinking it must be related to the local outlook client but not finding anything to back that up.

Maybe I should just reinstall? Repair?
Yes its related to outlook, as mails are going through OWA.
Is this for all users or machines or for a particular user or machine.
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Right now it seems to be 3 users and 3 different machines. It also appears that it isn't just one domain (sending to) but it isn't all of them.

In one case, if she replied to an email within OWA, she got a kick back, but if she created new email from OWA, it went thru.
First I would correct that warning about reverse DNS.
First part you can configure at your server:
The second part:
You must ask your ISP provider to set rDNS record on IP address of your internet connection to the same value you have specified as A record of your mail server and also specified as FQDN on SMTP virtual Server.


We also use Google/Postini. We are seeing a reinjected status on the trouble maybe there is something there. Troubleshooting with Google now :)
Update, the issue was on the recepient side. Either our domain or the user email address got black listed. We contacted the IT department and they reviewed with McAfee ( and got it corrected.


Issue resolved.

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