google.com is not opening on mozilla firefox on ubuntu

Trying to open google.com in mozilla firefox in ubuntu ,getting the message

"This Connection is Untrusted"so i clicked on "I understand the risk" then "Add exception"and then"Confirm security exception"

Still same error is coming

When i open the certificate ,The heading is "Could not verify this certificate because the issuer is unknown"

1 Answer

I think that is because of proxy, you can change it as "No Proxy". Go to

preference >> Advanced >> Network >> Settings >>"No proxy"