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Mail Delivery Fails with "unknown host or domain" (Doc ID 1905659.1)

Last updated on JANUARY 31, 2024

Applies to:

Oracle Communications Messaging Server - Version 5.2.0 and later
Information in this document applies to any platform.


How to debug configuration problems when the MTA is rejecting mail with an error message like:

Note: the <domain> part may very well be a valid domain, which adds to the confusion of why is it saying "unknown host or domain"?

Troubleshooting Steps

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In this Document
Troubleshooting Steps

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