Email rejected due to domain's poor reputation

Remote Server at 'mail server' returned '400 4.4.7 Message delayed'
4/16/2015 1:18:16 AM - Remote Server at 'mail server' returned '451-4.4.0 Primary target IP address responded with: "554-quarantine.domain 451 4.4.0 554 Your access to this mail system has been rejected due to the sending MTA's poor reputation. If you believe that this failure is in error, please contact the intended recipient via alternate means.." Attempted fail over to alternate host, but that did not succeed. Either there are no alternate hosts, or delivery failed to all alternate hosts.

I could not find any reference to our domain being blacklisted anywhere. I did find it with a 'neutral' status which it seems to be common.

Any suggestion on what else I could try?

Thank you!
Alan DalaITAsked:
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Dave BaldwinFixer of ProblemsCommented:
You'll have to do what the message says, "contact the intended recipient via alternate means.." because you're getting in the current way.  If you have a Gmail account, you can try that to tell them that you're not being allowed to send email to them from your regular account.

There are quite a few mail servers that operate on 'reputation'.  Microsoft's Live Mail / Hotmail does and so does Yahoo to some degree.  It doesn't mean that you are technically balck-listed but it does mean they don't like you for some reason.  It is almost impossible to find out why.

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Sometimes, the recipient has no control over this issue (automated spam reputation system). In that case, you should have a backup SMTP server ready. Hopefully you sent this mail out by yourself, so the backup SMTP server could be the one provided by your ISP. If you already use the one by your ISP, then it will be more difficult.
Let's just say you did send out the first one by yourself, and you have a backup smtp server from your ISP, you just configure your exchange to send out the mail to that SMTP server only to that domain (instead of send connectors, I usually add an MX record instead)
IvanSystem EngineerCommented:

you can test your domain or ip reputation at site: (I would check both with domain name and public ip from your mail server).
Make sure you have all public DNS records in place. I had a client that did not have SPF records and this problem.

While reputation is low, if you can contact that remote mail server admins, and ask them to put you on whitelist.

Zacharia KurianAdministrator- Data Center & NetworkCommented:
Mostly it could be related to your MX records. Could verify your MX records as suggested by @spriggan or you can check it out with

One of my client had a similar issue and it was related to reverse DNS.

Md. MojahidCommented:
If you were blacklisted, then a server that has been setup correctly would reject the email immediately with a failure code. Anything else is a sign of a badly configured server. Delay messages are usually because of a routing issue or something like greylisting, which delays the message and forces the server to resend later. The idea being that spammers will not try again.

As for diagnostics, you are completely dependant on the remote email server admin putting something useful in the NDR. However I tend to find that badly configured servers will mean bad NDRs.

The NDR text isn't generated from your server.
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