I keep getting the "Safari can't establish a secure connection" message when I try to log in to Facebook.

And Safari can't establish a secure connection to discussions.apple.com either so I can't get support there.

Other sites appear okay so far.

Hope someone can clarify here for me.

Edit:
Safari eventually appears to be now making secure connections. No changes made to configuration.

Edit:
Spoke too soon. Problem reoccurred. ANY https site results in Safari unable to establish a secure connection, including discussions.apple.com

Any solutions?