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Why is Outbound mail on the ESS showing a Delivery Status of Deferred (No response to HELO/EHLO)?

  • Type: Knowledgebase
  • Date changed: 7 months ago
Solution #00006717

Email Security Service


The outbound timeout on ESS servers is 45 seconds. 

If the recipient's server is taking longer than 45 seconds to return their 220 banner then the connection is deferred back to the sending server to be retried. 

It could also be because the recipient domain does not have a current MX record...sometimes it could be a simple misspelling. 
Confirm the domain MX record by performing a 'dig MX <domain.com>' and/or at mxtoolbox.com. 

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