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lava_za's avatar
lava_za
Copper Contributor
Aug 27, 2020
Solved

Error: 550 5.4.300 Message expired -> 451 Temporary local problem - please try later

Greetings, 

 

Since moving a specific domain to Office365 mails going out to a few domains always end up being returning with the above error 451 Temporary local problem.

 

Then after a while the I see from the Exchange Admin center, mail flow - there was a error and then later a successful delivery.

 

The domain is not listed anywhere as spam, and the recipients have also white-listed the domain.

Here is an example;

 

Reason: [{LED=451 Temporary local problem - please try later};{MSG=};{FQDN=securemail-mx1.synaq.com};{IP=196.35.198.158};{LRT=8/25/2020 8:02:56 AM}]. OutboundProxyTargetIP: 196.35.198.158. OutboundProxyTargetHostName: securemail-mx1.synaq.com

 

Reason: [{LED=550 5.4.300 Message expired -> 451 Temporary local problem - please try later};{MSG=};{FQDN=securemail-mx1.synaq.com};{IP=196.35.198.158};{LRT=8/26/2020 7:22:49 AM}]. OutboundProxyTargetIP: 196.35.198.158. OutboundProxyTargetHostName: securemail-mx1.synaq.com

  • This looks like a case of graylisting… best work with the other side to add an exception for your domain or similar.

2 Replies

  • This looks like a case of graylisting… best work with the other side to add an exception for your domain or similar.

    • lava_za's avatar
      lava_za
      Copper Contributor

      VasilMichev Thank you kindly for the reply, your suspicion was correct as the recipient mail server filtering had a static IP bound to the sender that was the old MX records, and hence it was permanently placing the sender in a grey-list. 

      Solved by requesting a removal.

       

      regards,

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