See if you can find that certificate exception here:

• Firefox > Preferences > Advanced > Encryption: Certificates > View Certificates : Servers

I have often visited the site of my former college. It's a small college that doesn't specialise in IT so it didn't surprise me too much that their security certificate wasn't up to date and I had typed the address accurately. I accepted the risk and was taken to a site unrelated to my college - scarey! I then entered my college's site successfully by using a link in a search engine, Everyclick. I'll probably want to visit the authentic college site in the future.

I looked through the list of certificates described by Cor-el but it wasn't there. Is there anything I can do to protect myself from the incorrect site?

When I was looking for the certificate to delete, I was looking for a certificate with a name similar to the name of my college.

I run Firefox 7.0.1 in Ubuntu 10.04.

Tools>Options>Advanced>Encryption>View Certificates

Then check under each category and if you find yours, choose it and delete.

You can connect to the site that uses the certificate and open it in a tab to see which certificates as shown in the certificate chain.

You can click the Site Identity Button and click More > Information > View Certificate

• https://support.mozilla.com/kb/Site+Identity+Button