Encoutering proxy errors using Linux

[Xyncgas]

Using Linux, Fedora distro
Enabled proxy by typing proxy in kde desktop's start menu, set proxy to manual configuration, the webkit browser photino using would fail loading all images / iframes / etc that are with valid url (https://...)

The proxy I set up works, while I use firefox's own proxy setting to use the proxy address I set in the system configuration also works, disabling the setting for proxy in system configuration works

I had the proxy running at 127.0.0.1, it was a socks5 proxy
The error message logged in the browser's console was : Failed to load resource: Unspecified proxy lookup failure