How to view certificates for mail servers?

Thunderbird periodically ask you if you approve adding exception for mail server certificates. After such certificate is added, how to view, edit, or remove it?

I found it


  1. Using Thunderbird, navigate to Edit > Preferences > Advanced > Certificates > Manage Certificates

  2. Using the “Certificate Manager” window, click on this “Servers” horizontal tab

  3. Using this “Servers” horizontal tab, you are able to view or delete certificate

This “Servers” horizontal tab collects only exceptions that you have manually approved. It does not cache CA-validated certificates. This is normal.

If you need to view CA-validated certificates, the other steps below are one easy and free way to do this.

Steps to view CA-validated certificates:

  1. Using your favourite internet browser, such as Firefox 91, go to the URL hosting the mail server certificate. For example, go to

  2. Using Firefox, click on the small lock button. Which is located on the left side of the URL field.

  3. Click on the ~“Secured connection” line

  4. Click on ~“More information” line

  5. Click on ~“View certificate” button