https://www.ssllabs.com/ssltest/analyze.html?d=racenet.codemasters.com

Warning: Inconsistent server configuration

??? How I interpret this?

The server uses a broken encryption and needs TLS 1.0

Broken Encryption (TLS_RSA_WITH_RC4_128_MD5, 128 bit keys, TLS 1.0)

The website may try to fallback to TLS 1.0 in a way that is no longer allowed in current releases or may be using a deprecated cipher suite.

You can open the about:config page via the location/address bar and use its search bar to locate this pref:

• security.tls.insecure_fallback_hosts

You can double-click the line to modify the pref and add the full domain (racenet.codemasters.com) to the value of this pref. If there are already websites (domains) in this list then add a comma and the new domain (no spaces). There should only be domains separated by a comma in the Value column (example.com,www.example.com).

If this helps then you can contact this website and ask them to look into this and update their security.

• https://developer.mozilla.org/en-US/Firefox/Releases/36/Site_Compatibility#Security
• https://developer.mozilla.org/en-US/Firefox/Releases/37/Site_Compatibility#Security
• https://developer.mozilla.org/en-US/Firefox/Releases/38/Site_Compatibility#Security

I solved the problem by changing security.tls.version.fallback-limit value was set to "3" I changed to "1" and now the page loads correctly.

It is not advised to set the security.tls.version.fallback-limit to 1 as this is a security risk. It should be sufficient to add involved domain(s) to the whitelist pref security.tls.insecure_fallback_hosts.

Did you try that?

Yes, but the page doesn't load correctly (no graphs, only text not displaying correctly) and after clicking the link (where it should display a button or custom 'login' graph) then it goes back to the same Connection Failed screen