Checking Existence of the Certificate Using Firefox

Note 1: The [Issued To], [Issued By] and [Expiration] in the screenshots are just examples and will be different from those for the actual certificate.
Note 2: All screenshots are from Windows10 (Firefox 58.0).

1. With Firefox, click on the [Menu] icon and select [Options].
   
   
   
2. In the [Options] tab, select the [Privacy & Security] in the menu, and click [View Certificates...(C)].
   
   
   
3. In the [Certificate Manager] screen, click [Your Certificates] and make sure that the certificate appears in the list.
   Select the certificate and click [View (V)].
   
   
   
4. In the resulting [Certificate Viewer] dialog box, select the [General] tab and make sure that it says "This certificate has been verified for the following uses."
   
   
   
5. Select the [Details] tab and make sure that all certificates from the Root CA through the client certificate are correctly chained.
   Note: The screenshot is an example and may show different path tree from the actual state.