WS2022 IIS SMTP Server doesn't find TLS cert

JRV 551 Reputation points
2022-12-22T22:34:13.807+00:00

We use an IIS SMTP server to relay emails from older scanners that don't support TLS to MS365 anonymous relay, which requires TLS. We're replacing an existing WS2012R2 server with SMTP with a new WS2022 server with the SMTP feature installed.

The WS2012R2 SMTP server finds its TLS cert. The WS2022 server does not.

We have a CNAME for the WS2022 server in internal DNS, 'relay.domain.net'.

We have a self-cert whose subject is 'relay.domain.net' in the Personal and Trusted Root CA's stores of Certificates.msc. When I open the cert, it shows, "You have a private key that corresponds to this certificate.", and Certificate Status is "This certificate is OK."

In the SMTP Virtual Server, Delivery-->Advanced-->Fully-qualified domain name is set to 'relay.domain.net', and Check DNS reports the name is valid.

Pretty sure that's all I've ever had to do to get the cert to be used by SMTP service on any other Windows Server in the past.

But here, I restarted the SMTP service--and for that matter, the server--and the Access tab still reports "TLS is not available without a certificate," and the Windows Service event log shows smtpsvc event 2001, "No usable TLS server certificate for SMTP virtual server instance '1' could be found. TLS will be disabled for this virtual-server." as the SMTP service starts.

Am I missing something? If not, is there a place I can kick it to make it work?

Windows development | Internet Information Services
Windows for business | Windows Server | Devices and deployment | Configure application groups
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  1. Lex Li 6,037 Reputation points
    2023-01-08T16:49:29.7+00:00

    All Windows/IIS SMTP components became deprecated ever since Windows Server 2003 went end of life,

    https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/hh831568(v=ws.11)#smtp

    So, use search engines to see what alternatives (likely from third parties) you can migrate to.


  2. Feller Tomáš 0 Reputation points
    2025-01-02T12:04:13.8766667+00:00

    For me, the only way was create certificate request in IIS MMC and sign it in internal CA. Because I have two balanced SMTP servers, I have to use only the balanced common name in the request and do it twice. Even though such certificate has no SAN (IIS request does not allow to add SAN), it works.

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