Need to add Let's Encrypt certificate manually to Certificate Store

[peter4]

I created Let's Encrypt certificate via win-acme (GitHub - win-acme/win-acme: A simple ACME client for Windows (for use with Let's Encrypt et al.)) on Windows Server 2019, it works beautifully for my websites in IIS.
I also have an old server running Windows Server 2016, which runs Mail Enable.
And I'm now also configuring Mail Enable on my 2019 server.

In Mail Enable on my 2019 server I noticed that I can't select that SSL certificate in the dropdown Default SSL Certificate settings of Servers > Localhost -> Properties -> [SSL] tab, it's just not showing up.

So I compared my Windows Certificate Store on my old server (Windows Server 2016) and I noticed that there it has the Let's Encrypt certificate in Local Computer > Personal -> Certificates, whereas on my 2019 server it's missing.

I don't remember how I configured it on my old 2016 server anymore, but I think I just need to add the Let's Encrypt Certificate to this Local Computer store for MailEnable to allow it to be selected on the SSL tab.

How can I add the certificate I already created on my 2019 server to a specific Certificate Store?

I checked other suggested topics here, but I could not find the literal steps I need to take:

Please help install the Let's Encrypt certificate

a…

[rg305]

The problem seems very specify to Windows Certificate Store and the Win-ACME client.
Have you tried asking for help directly from them?
[https://www.win-acme.com/support/]

[webprofusion]

Hi, check the Web Hosting store instead of the Personal Store. I think maybe win-acme defaults to the web hosting store but you can change it in your settings win-acme

You can export (with private key) the existing PFX then re-import it into the personal store, or you can just fix your settings in win-acme and re-run the certificate request.

As an aside, some apps choose to store certs under Web Hosting because it's purported to be more efficient but I have yet to find any actual evidence that it makes any performance difference at all, other than a woolly statement on the microsoft docs page from a decade ago.