ESMTP #554 Transaction Failed Spam Message not queued. ##

My team Received always NDR message (ESMTP #554 Transaction Failed Spam Message not queued. ##) when they send for some domain and i tried to telnet the domain but i received the error : 421 4.3.2 Service not available, closing transmission channel
i have exchange 2007 sp3
please any solution for this problem
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csh2010Asked:
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evanmcnallyIT ConsultantCommented:
The 421 error could mean a problem on their side, or could just mean a firewall that does not like the telnet test trick but would accept communication from your server, or could be a consequence of being on a black list.

If you are getting NDRs, you are presumably sending mail successfully as far as their server where they are then choosing to spam filter you.

1.  See if your email server's IP address has been black listed:  http://www.dnsbl.info/
2.  Make sure you have reverse DNS records for your mail server
3.  If those don't work, do you have the option to contact the other organization and ask for their mail admin to allow your domain?



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psalkiewCommented:
Please check if the IP address you're connecting from has a correct reverse dns record. Some mail servers reject machines without rev-dns without saying a word.
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JamesSenior Cloud Infrastructure EngineerCommented:
Please check if they have put your Domain/IP into their AntiSpam as a black list. You might not be on Public RBL but could be on theirs.

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