''locking as duplicate of [https://support.mozilla.org/en-US/questions/1014430 /questions/1014430]'' Hallo We recently purchased a certificate from Symantec. It's intermediate authority is Symantec Class 3 EV SSL CA - G2, but Mozilla firefox doesn't seem to trust it. Other browsers (IE and Chrome) have the certificate chain trusted. Is there a way to add this certificate chain in Firefox, because many of our clients using Firefox are complaining and asking about our site's security.