If you playing around with proxy stuffs without knowing wtf proxy is, you might end up to a problem like me. Suddenly, my Firefox rejecting to connect to the internet. What a frustration seconds. However, i found out that a proxy app i tried out earlier set my Firefox’s proxy to ‘manual’.
To fix it out, simply click on (updated by reader Red on comment below) Tools > Options > Advanced > Network > Settings. Then simply tick a ‘No Proxy’.
That’s it, enjoy Firefox and the internet.