From out of nowhere my Gmail on iPad(2) has started doing something odd. I've spent most of the evening looking for a solution and haven't found one, so any help will be much appreciated...

Basically, it receives email just fine, but I can't send it. I've tried turning the iPad on and off, deleting and reinstalling the email account, using 3G and WiFi, but still the programme just gets stuck on 'sending', and nothing happens. The odd thing is that I have exactly the same settings on my phone (4S) and it's working just fine, so I'm stumped as to what to do - any thoughts?