This error applies to Mac OS X 10.8.5 and Safari 6.2.8 when you attempt to access secure pages. This version on Mac OS X and Safari does not support our updated SSL version.
As a workaround, copy and paste the URL into an alternate web browser such as Google Chrome or Mozilla Firefox. Both of which are free to download and easy to install. This should allow you to authorize nugs.net secure pages.
Or try this: "Turns out it was my Mac antivirus that was causing the "Safari can't Establish a secure connection". All website are working after I disabled the Web Shield in my antivirus setting."