I hadn’t used Firefox in a while and needed to do a bit of cross-browser testing. I fired it up and got a strange and seemingly random error where it wouldn’t connect to some web sites. Just got an “Unable to connect” error page.
I quickly worked out that it ONLY allowed secure sites to load, anything with https:// at the beginning. Did the usual Google search but got a mixture of Windows solution saying turn off anti-virus or Mac solutions where people cold only connect to non https sites. Hence me writing this post, just in case you’e going through the same process.
I have Little Snitch installed, which allow you to selectively allow or deny network access as and when they happen. You’ll be surprised at how much applications constantly send to and from their servers! Anyway, it was Little Snitch blocking traffic on port 80.
Not sure why there was rule in place in the first place as it shouldn’t need one for top-level access, so they could be deleted.
And now it works. Hope it helps you out!