Unable to send emails to another ESS client
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Unable to send emails to another ESS client


Article ID: 263423


Updated On:


Email Security.cloud


Messagelabs customers are unable to email another client of the ESS when their domain is still active but pointing to another vendor's MX records.

Error received :  "421 4.4.0 [internal] no mail servers for this domain could be reached at this time"  This error is common, but mostly will be seen in such a scenario.




The receiving domain is not using the clusters assigned to them initially, but they are pointing to a different MX records.


There are 2 solutions in order to quickly resolve the Issue :

1 - The recipient's domain owner or Admin should remove the domain from the client net portal, if they are sure that the domain will not be using our services.

2 - The domain should be using our MX records as assigned to them during the provisioning process

Note : In case when the client is not willing to use our services and they would like to cancel it , they are advised to contact our Cancellation Team.

KB will explain the required steps in order to cancel a service.