Turns out, it was a conflict with my antivirus (ESET Smart Security 8).
In case anyone else faces the same problem, the solution is to uncheck "Enable HTTP checking":

http://i.imgur.com/0mPdumK.jpg?1

(Unless you know what "Ports used by HTTP protocol" is, and which one FileBot/OpenSubtitles uses)

1- API is down.
2- Servers generally overloaded.
3- IP blocked.

Number 2 and 3 aren't an option because I've tried manually getting on OpenSubtitles and downloading subs and everything works fine. I also used a VPN and FileBot still didn't fetch the subs. Also, if there was a problem with the ...

I have tried 4.5.2 and it asks for login information which OpenSubtitles itself doesn't require, so I switched back to 4.5

Console:

http://i.imgur.com/vp0Mscr.jpg?1

http://i.imgur.com/WtWc0My.jpg?1

http://i.imgur.com/RbiFjw5.jpg?1

Sorry, I also forgot to mention that this only started happening as soon as I updated to the latest version 4.5

If there's something in specific that you need to know, ask me; but other than ...

Maybe the files are write-protected a.k.a Read-Only.

I've been using FileBot for a while now and I gotta give it to you guys, this is an awesome program.
I always use it to download subtitles and it has been doing a great job at it ever since I started using it; but a little while ago, it sopped fetching the subs.
The program still works and all, it ...