Comment 18 for bug 95241

I had the same problem and I am not behind an HTTP proxy. Perhaps there is some proxy software in the picture that my company uses that causes this. Changing the user agent string to remove "Feisty" fixes the problem.

Unfortunately, I faced the same problem with liferea that uses mozilla as backend. Changing the user agent string for liferea is more involved because you have to dig through .liferea directory to find prefs.js and edit it.