Sometimes servers get restarted/go down etc. If you get kicked, the message will say you've been kicked(and there should be a reason, too, but it might be nothing because it's optional to fill out I think).
Yay, I wasn't kicked.
The other night the EA servers went down, that sucked, everyone on vent at once asking "Did anyone else get disconnected?" lol
For all I know it might have been EA servers I was on last night. I honestly can't remember. Anyways, I set up my ports per the instructions and that should improve my odds.