It sounds like you are trying to access a certificate-protected page. You can confirm that you have a working certificate installed by going to
http://web.mit.edu.ezproxyberklee.flo.org/certificates/test/
and clicking on the "Test my certificate" link on that page. If the next page does not load properly, you will need to install a certificate by following the instructions at
https://mv-ezproxy-com.ezproxyberklee.flo.org/ca/
Once you have installed the certificate, please re-launch your web browser and try again.
Thank you!