TLS mechanism

OSX 10.9.5, Firefox 51.0.1 uptodate as of now.

Entered various site URLs:

https:// online-go.com, online-go.com/, w-ww.online-go.com, w-ww.online-go.com/ get:
Secure Connection Failed: The connection to online-go.com was interrupted while the page was loading. The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.

Cleared everything, start fresh. Open new window, clicked Tools, Web Developer, Network and then enter h-ttps://online-go.com

I see one line with a GET and grey padlock with red slash. That’s all. Nothing I can find anywhere about encryption. Where am I supposed to be looking for this?

There’s an ( i ) icon in the address field that gives page info. It says the Connection is not secure, This website does not supply ownership information, and Connection not encrypted, website dos not support encryption for the page.

For comparison I loaded h-ttps://www.dragongoserver.net

Compare the screenshots of the two Page Info windows info window:

When I load OGS, Console shows:
2/26/17 12:23:20.601 AM Console[15133]: Marker - Feb 26, 2017, 12:23:20 AM
2/26/17 12:23:30.388 AM com.avast.proxy[283]: SecTrustEvaluate(): online-go.com: 7
2/26/17 12:23:30.391 AM com.avast.proxy[283]: SSL_accept(): Broken pipe

When I load DGS, Console shows:
2/26/17 12:25:24.706 AM Console[15133]: Marker - Feb 26, 2017, 12:25:24 AM
----nothing logged—

I disabled Avast Online Security (Browser Security and Web Reputation Plugin) in Safari Preferences. Still get same message in Console when I load in Firefox. Uninstalled the Extension. I still get the same problem and still get the same Console log about com.avast.proxy. Maybe I need to relaunch Safari or restart. Quit. Activity Monitor shows com.avast.proxy in the process list under Root and inactive. Launch Safari and it springs to life. I have no idea what it does, maybe it’s part of the AV and not that extension.

Avast also delivered an update and there was a problem with it generating false positives; that has been fixed.

Possibilities: You understand something and provide more guidance. Cleaning out some stuff like caches, saved app. states and Restarting. Reinstall Avast.