hello, first please make sure that the date, time & timezone are set correctly on your system. if this doesn't solve the issue (or it is already set properly), a possible solution depends on different factors:

• what is the error code shown under technical details on the error page?

in case the error code equals sec_error_unknown_issuer, please attempt to add an exception on the bottom of the error page in order to inspect the certificate like it is shown on the screenshot attached:

• which issuer information does the certificate contain?

please report back with those two pieces of information. thank you!

Date and time are set correctly.

Error code is exactly the error you listed above.

Issuer information is: Avast trusted CA

ok thanks, so it looks like avast is intercepting all your encrypted connections and isn't properly set-up to so - also see http://www.thesafemac.com/avasts-man-in-the-middle/

please try to disable https scanning within avast (i hope the same steps apply to os x as well):

1. Open the Avast dashboard on the affected system.
2. Select Settings from the left sidebar menu.
3. Switch to Active Protection.
4. Click on Customize next to Web Shield.
5. Uncheck the "Enable HTTPS Scanning" option and click ok.

http://www.ghacks.net/2014/10/31/avasts-https-scanning-interferes-with-firefox-and-other-programs/

Thanks for the info. Sadly, it doesn't work the same on osx. I see no way to switch to Active Protection and there is no button that says customize next to the web shield. When I click the settings button next to the web shield there is no option for Enable HTTPS Scanning at all. Looks like I'm uninstalling Avast now...