Classila 9.3.3 not able to connect to AF

As I tinker around, I sometimes use my different devices to connect to the internet. Sometimes I am looking for something here on AF, sometimes no. On this occasion, I was using my PDQ Powerbook (aka Enterprise) which runs Classilla 9.3.3. I am unable to get past the home page for AF at all. I get an error message about the site and the browser not having any common security algorithms. I know I have connected before from this laptop as my userid and password were populated into the login fields. Not sure when things changed but I am sure 'something" did. Can someone give me a shove in the right direction on resolving this or has the obsolescence demon reared its ugly head?