Problem sending to prod.outlook.com server | MDaemon Technologies, Ltd.
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Problem sending to prod.outlook.com server

  • M

    Hello everyone,

    our installed Mdaemon server hosts several email domains.
    Lately, on a couple of occasions, it has happened that some users were unable to send emails from our server to some domains, while sending was successful from other email servers (e.g. Gmail).

    Checking our Mdaemon I found several messages in the Retry queue and doing some checks in the logs I found a lot of messages of this type:


    451 4.7.500 Server busy. Please try again later from [our IP server]. (S77719) [AM3PEPF0000A798.eurprd04.prod.outlook.com 2024-03-26T15:16:19.739Z 08DC46BF534B716F]

    I checked if our public mail server IP was in any black list, but I didn't find any problem with it.

    Strangely, after a few hours the problem resolved itself automatically.

    I would like to understand if the problem is something related to our configuration or the "prod.outlook.com" servers had some anti-spam update that was creating these problems.

    Thanks in advance to anyone who can help me understand where the problem might be.

    Max

    0 likes
  • A

    I found this discussion that may be helpful.

    https://learn.microsoft.com/en-us/answers/questions/1388554/deferred-mail-with-error-451-4-7-500-server-busy-w

    --
    Arron Caruth

  • M

    Thank you Arron!

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