NDR: "451 All MX servers are unavailable for domain <domain.tld>" when sending outbound through Symantec Hosted Mail Security

Article:TECH89482  |  Created: 2008-01-08  |  Updated: 2008-01-09  |  Article URL http://www.symantec.com/docs/TECH89482
Article Type
Technical Solution

Issue



You send a message outbound through Symantec Hosted Mail Security. Your mail servers generates an Non-Delivery Report (NDR) which includes the text "451 All MX servers are unavailable for domain ".


Solution



Confirm that your MX records are properly configured within the Symantec Hosted Mail Security portal.
  1. If your MX records are correct, please obtain the following evidence, then contact technical support:
    • Screenshot(s) of the MX record screen within the Hosted portal which show whether the MX Record Analysis are the same as the Recommended MX Record settings
    • Headers from three NDR's which the original sender received
    • Mail logs from the target server(s) which match the three NDR's. These logs should show the IP address and/or hostname of the server in the Symantec Hosted Mail Security array which is associated with this behavior.


To confirm your MX records
  1. Log into the Hosted Mail Security portal with at least domain administrator credentials.
  2. Click Email Defense.
  3. Click Setup.
  4. Click MX Records.

If the MX records returned by the MX Record Analysis are not the same as the Recommended MX Record settings, please consult your DNS administrator.






Legacy ID



2008050815035554


Article URL http://www.symantec.com/docs/TECH89482


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