I believe that there's no SSL certificate for the site.
The hosting company makes one available to you (that's a fairly new thing). Need to make sure it's turned on for this domain.
As for why it's showing up now, it's a new thing with browsers. They're all going to be raising that alert going forward.
It was a nice idea. Make the Internet safer for everyone. "Don't fill in that form unless you see the lock in the address bar." yada yada yada
The problem is that certs are free for hackers too. So, you can make up a fake banking site and get a cert to make the lock appear in the address bar.
If that's someone's only criteria for evaluating the safety of a site before giving it your info or credentials, then they're no safer than before all of this safety stuff came in to affect.
It's just created work for site owners. Sure there's a bit of value in having traffic between browser and even forum sites encrypted, but the whole idea was to address something else - and it missed.
yes, warning are still there due to the forum only responding in FF on HTTP and no HTTPS so when you auth, you're sending the user/pass unencrypted.
Secure Connection Failed
An error occurred during a connection to www.markweinguitarlessons.com. Cannot communicate securely with peer: no common encryption algorithm(s). Error code: SSL_ERROR_NO_CYPHER_OVERLAP
The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
Please contact the website owners to inform them of this problem.