iPhone logs me out of facebook?

[hockeygirll]

I just got a new iPhone yesterday and downloaded the Facebook for iPhone app, but every time I sign into Facebook it logs me out after about 2 minutes (or sometimes immediately). It will never log me back in after that, and I end up having to restart the phone. I tried clearing my cookies, setting the cookies to "Accept Always", taking all the other apps off my phone, reinstalling the app (about five times), and resetting the iPhone, but nothing has worked. Nobody else that I know (in my family or at school) with an iPhone is having this problem, though I've seen other people online who have. Does anyone know of a solution?