Exchange 2016 - IMAP/SMTP Auth on port 587

LuLaCeK 1 Reputation point
2021-08-02T14:18:27.4+00:00

Hi guys,
need help with Outlook, to use smtp port 587 for outgoing mail.
The problem is, I cannot authenticate user on port 587 (Client Frontend Connector), but if I change SMTP port to 465 (Client Proxy connector), then AUTH is working.
The port 25, for anonymous is working, but I want to AUTH users. Why is port 465 working and 587 is rejecting AUTH?

119895-auth587.png

Here are connectors permissions:
119864-exchange-setup.png

Here is the log of "Client Frontend connector":
119985-119829-log.png

And here is the connector cert:
119879-connector-setup.png

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. LuLaCeK 1 Reputation point
    2021-08-03T13:27:10.97+00:00

    Hi @Kael Yao-MSFT

    External client (Office 2016)

    120089-outlook-outgoing-server.png

    120168-outlook-advance.png

    120188-error.png

    But, when I change port to 465, AUTH is working, same user name, same password. Just port is changed.
    120223-465.png

    120204-465-2.png

    On Internal client (Office365 Client) is the same problem, but when i change port to 465 again, it is working:

    120157-internal-587.png
    120069-internal-error.png