I opened my iPhone app and strangely, although I had been signed up earlier this morning, it asked for sign in credentials and has been spinning for the last few minutes.
Server problems maybe? If it is maintenance then it would be nice to have a heads up before it happens.
UPDATE: Shut it down giving up and restarted and working fine. Sadly all of my downloaded books are no longer downloaded. This is a real problem. This has happened a number of times and makes me think that downloading books is a waste as they will just get deleted soon when I am logged out.