Hi On a couple of occasions I have been unable to get to a particular website. I can’t recall what the previous problem websites were and those problems were corrected within a couple of days, but the latest (todays) problem is with Amazon. Here is the error message I received: An error occurred during a connection to www.amazon.de. Invalid OCSP signing certificate in OCSP response. Error code: SEC_ERROR_OCSP_INVALID_SIGNING_CERT My google searches reveal the following solution (which works for me) from https://support.mozilla.org/en-US/questions/1161980 : You can temporarily disable OCSP Stapling : Type in the address bar about:config (press Enter) (promise to be careful, if asked) Type and look for the preference : security.ssl.enable_ocsp_stapling and set it's value to false It is best to reset this pref via the right-click context menu to true once you are done with this website. My question is what does security.ssl.enable_ocsp_stapling do and why do I need to disable it to get some something like Amazon to work? Thanks