So, everytime I go to the home page on twitter, on my iPhone, it says, "Error loading tweets (400) tap to retry" it was working perfectly fine before, so why is this happening now? Even when I try going to people's twitter pages it doesn't let me see their tweets, or who they follow. I tried deleting the app and re-installing it again, but it still pops up like that. Please help me, what can I do? Thanks:) x

Is every other app working on your phone?
that happened to me before as well, but it affected my facebook and other social networking apps too.
if it does, try reseting your network connection in the settings (turn off 3g and cellular data, and then turn them on again), and then restart your phone.
it should work!