It's probably because you haven't enabled proper port forwarding on your router.
Oh you have?
It's probably because you haven't allowed an exception for Origin in your firewall.
Oh you have?
It's probably because you haven't uninstalled and re-installed Origin, deleted it's cache or re-downloaded SWBF.
Oh you have?
It's probably because your ISP, the world's seventh largest and US' second-largest, is blocking access specifically to SWBF but will let you play any other game online.
Oh they're not?
It's probably because you're a technical neophyte and not an Optical Engineer with Cisco Systems since 1999.
Oh, you are too?
It's probably because you trusted a game developer and publisher to deliver on their promises.
Sadly, I did. Over a week and have only been able to play in 1 online match.
It's all OK, though. We're part of their acceptable-loss strategy.