the server you are connected to using a security certificate that can not be verified

Howdy -- are you using a self-signed certificate there? That error would occur when using a self signed certificate, you would need to use one that's trusted by the various web browsers and email clients.

If you've already setup a trusted SSL certificate, you can go into Server Configuration -> Manage SSL Certificates, and there you can click the "Copy to Dovecot" and "Copy to Postfix" buttons.

You would first need to enable the "SSL Website" feature using Edit Virtual Server -> Enabled Features.

Then, you'll have access to Server Configuration -> Manage SSL Certificates.

From there, you can do two things.

One, you can obtain a commercial SSL certificate.

Or two, you can use the Let's Encrypt tab to obtain a free Let's Encrypt SSL certificate.

After you do one of those two things --

You'll then be able to copy that SSL certificate into your other services, such as Dovecot, Postfix, and Webmin.

What information in particular are you looking for?

You would only need that if you're purchasing a commercial SSL certificate though. What matters most in that case is the domain names mentioned in the "Other domain names" field.

If you are using the free Let's Encrypt certificates, you shouldn't need a CSR. In that case, the CSR is generated automatically.. though you'd need to make sure the appropriate domain(s) are listed in the "Domain names listed here" field.

If you browse to the website where you setup that SSL certificate, does it show up as working properly for that domain?

Also, just to clarify, did you copy the SSL cert into both Dovecot and Postfix?

If so, just to be certain, you may want to try restarting those two services:

Lastly -- be sure that when connecting to your server, that the hostname you're using is the one the SSL certificate is setup for.

What is the domain that you've setup this SSL certificate for?

What ports is Outlook attempting to connect to, for both incoming email, as well as outgoing email?

Also, can you verify that for both incoming and outgoing, that it's attempting to use the domain name "planetgrouprealty.com"?

Hi Andreychek,

I have this problem but I am unable to update the certificate with the correct domain. It has imap.example.com instead of my domain when I connect through Outlook. I am using a Let's Encrypt SSL. How can I update it in Postfix and Dovecot?

Thanks, Julius

Certificates can be copied into Postfix/Dovecot in Server Configuration -> SSL Certificates, and there, use the "Copy to" button.

It looks like you're using Virtualmin GPL there though -- it's no problem to get support, but if you have any followup questions, you'd want to use the Forums for those. We monitor the Forums, along with lots of wonderful folks in the community. Thanks!

Thanks, Andreychek! I will try your suggestion above.

My bad! I found this using Google. I thought it was from the forum.

Thanks again for your answer!

Julius