Problem with Firefox 38 Error Message: This Connection is Untrusted

Firefox 38 for Macs is blocking several https websites, including Goggle, with messages that read: "This Connection is Untrusted." The error message appears even after an "exception" is added to specific https websites like Google.

In Preferences > Advanced I have this option selected: When a server requests my personal certificate: select one automatically." Also, I have had the following option check-marked and uncheck-marked without it making any difference: "Query OCSP responder servers to confirm the current validity of certificates."

The following Mozilla Support page for this issue does not help to solve this problem. https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

I've included two screenshots of the errors that are commonly appearing in FIrefox 38 in my experience.

It's important to note that I have previously visited the https websites without a problem that are now being blocked by Firefox 38. Thanks for any tips on how to stop Firefox 38 from blocking safe https websites like Google on a regular basis.

 

Where do I look for that to check? Thanks.