hi, please enter about:config into the firefox address bar (confirm the info message in case it shows up) & search for bold preferences starting with security. - right-click and reset those entries to their default values.
That did the trick. I reset the following to their defaults: security.ssl.errorReporting.automatic (from true to false) security.tls.version.min (from 2 to 1)
What puzzles me is that I changed those values well over 2 (3?) years ago--why the problem now?