This issue has now been resolved so this notice is no longer valid.
The most recent update to Firefox (version 39) has implemented some new security standards that have broken the ability to connect to many websites. The error that you will see is as follows:
An error occurred during a connection to (website address). SSL received a weak ephemeral Diffie-Hellman key in Server Key Exchange handshake message. (Error code: ssl_error_weak_server_ephemeral_dh_key)
Unfortunately, at this time, the only way to work around this problem is to use a different browser such as Internet Explorer or Google Chrome. We are not the only ones affected by this change but we are working to resolve the problem.