returned '450 4.4.316 Connection refused [Message=Socket error code 10061]

onthejob 1 Reputation point
2023-11-29T18:51:40.6866667+00:00

Hi, I have migrated my exchange 2016 Org to 2019. Before I decommissioned 2016 I ran the exchange hybrid wizard and selected the exchange 2019 servers. I only have a handful of mailboxes in O365 but when they mail to on-premise I get the following error. returned '450 4.4.316 Connection refused [Message=Socket error code 10061] Any help would be great. Thanks

Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
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  1. Shaofan Lv-MSFT 6,610 Reputation points Microsoft Vendor
    2023-11-30T02:24:01.4766667+00:00

    Hello @onthejob

    I did some research. I found that this error seems to be related to port 25. Please try to unlock port 25. A10061 error is caused by either a firewall or anti-virus software presence on the local computer or network connection. please check this thread Sort by time Homer Sibayan's two answers.

    https://learn.microsoft.com/en-us/answers/questions/95373/unable-to-send-email-from-o365-to-exchange-2016-on

    Regards

    SF


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