Did you go to the Privacy & Security section of your Options to find the certificate to delete the certificate from there?

I don't see the certificate I overrode, which involves a security certificate for my website. I changed it in the sharing port on my Wordpress site and now it says the certificate is unrecognized. I can't figure out how to get into my Wordpress admin site to change it back. I thought overriding the certificate might work but it did not, so I'd like to undo the extension - which I don't see. Suggestions? (And thx for responding)

I also have one other question on certificates as I'm seeing quite a few from China, Turkey, etc. - I'm not sure where they've come from but should I get rid of those?

I also see that I have 2 Firefox's running - I've gone in and changed the settings but both are still there, and it is slowing my computer down greatly. Tx

Note that for exceptions you need to look at the Servers tab in the Certificate Manager.

Firefox comes with a lot of builtin root certificates used by Firefox users from all over the world and best is to leave them alone. There is no need to distrust builtin certificates that you see under the Authorities tab.