Hi Linda, I know you don't want us to point the finger at Kaspersky, but if this is an unknown issuer error (see the Technical Details section of the page), I do need to ask you to look at the certificate that Firefox is rejecting to see whether it has a non-standard issuer. For example, if you open the plugin check page: https://www.mozilla.org/plugincheck/ If you did not save an exception for this site, open "I understand the risks", click "Add Exception" then "View" to view the certificate. How does it compare with the red boxed areas (Issued by, Certificate Hierarchy) in the attached? You don't need to finish creating an exception; you can cancel out. (If you did create an exception for this site, click the padlock or warning triangle in the address bar, then More Information, then View Certificate.)

Thank you so much!